Gene Summary

Gene:TERT; telomerase reverse transcriptase
Aliases: TP2, TRT, CMM9, EST2, TCS1, hTRT, DKCA2, DKCB4, hEST2, PFBMFT1
Summary:Telomerase is a ribonucleoprotein polymerase that maintains telomere ends by addition of the telomere repeat TTAGGG. The enzyme consists of a protein component with reverse transcriptase activity, encoded by this gene, and an RNA component which serves as a template for the telomere repeat. Telomerase expression plays a role in cellular senescence, as it is normally repressed in postnatal somatic cells resulting in progressive shortening of telomeres. Deregulation of telomerase expression in somatic cells may be involved in oncogenesis. Studies in mouse suggest that telomerase also participates in chromosomal repair, since de novo synthesis of telomere repeats may occur at double-stranded breaks. Alternatively spliced variants encoding different isoforms of telomerase reverse transcriptase have been identified; the full-length sequence of some variants has not been determined. Alternative splicing at this locus is thought to be one mechanism of regulation of telomerase activity. [provided by RefSeq, Jul 2008]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:telomerase reverse transcriptase
Source:NCBIAccessed: 01 September, 2019


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 01 September 2019 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 01 September, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (9)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Entity Topic PubMed Papers
Brain Stem Glioma, ChildhoodTERT and Brain Stem Glioma, Childhood View Publications225
Lung CancerTERT and Lung Cancer View Publications149
Liver CancerTERT and Liver Cancer View Publications142
Breast CancerTERT and Breast Cancer View Publications119
Brain Tumours, ChildhoodTERT and Brain Tumours View Publications191
MelanomaTERT and Melanoma View Publications115
Acute Myeloid Leukaemia (AML)TERT and Acute Myeloid Leukemia View Publications84
Thyroid CancerTERT Promoter Mutations in Thyroid CancerPrognostic
TERT promoter mutations have been reported to be more prevalent in aggressive types of thyroid cancers (Liu X. et al, 2013 and Landa I. et al, 2013) and associated with BRAF V600E mutation (Liu X. et al, 2014) and as a prognostic indicator in differentiated thyroid carcinomas (Melo M et al, 2014). TERT promoter mutation is indicated to be an early genetic event in follicular thyroid adenoma (Wang N, et al, 2014).
View Publications79
Adrenocortical CancerTERT and Adrenocortical Carcinoma
Assié, et al (2014) identified recurrent alterations in TERT in a GWAS study of 45 Adrenocortical carcinomas, with results verified in a further independent set of 77 samples.
View Publications10

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: TERT (cancer-related)

Kutahyalioglu M, Nguyen HT, Kwatampora L, et al.
Genetic profiling as a clinical tool in advanced parathyroid carcinoma.
J Cancer Res Clin Oncol. 2019; 145(8):1977-1986 [PubMed] Related Publications
CONTEXT: Parathyroid carcinoma (PC) is a rare endocrine malignancy with no approved systemic therapies for unresectable locally invasive or distant metastatic disease. Understanding the molecular changes in advanced PC can provide better understanding of this disease and potentially help directing targeted therapy.
OBJECTIVE: To evaluate tumor-specific genetic changes using next-generation sequencing (NGS) panels.
DESIGN: All patients with advanced PC were tested for hot-spot panels using NGS panels including a 50-gene panel, a 409-gene panel if the standard 50-gene panel (Ion Torrent, Life Technology) was negative or a FoundationOne panel.
SETTING: The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
PATIENTS OR OTHER PARTICIPANTS: 11 patients with advanced PC were selected to undergo molecular testing.
MAIN OUTCOME MEASURE(S): Genetic profiles of advanced PC.
RESULTS: Among the 11 patients, 4 patients had the 50-gene panel only, 6 had 409-gene panel after a negative 50-gene panel and 1 had FoundationOne. One patient who had 50-gene panel only also had his metastatic site (esophagus) of his tumor tested with FoundationOne. The most common mutations identified were in the PI3 K (PIK3CA, TSC1 and ATM) (4/11 patients) and TP53 (3/11) pathways. Genes not previously reported to be mutated in PC included: SDHA, TERT promoter and DICER1. Actionable mutations were found in 54% (6/11) of the patients.
CONCLUSIONS: Mutational profiling using NGS panels in advanced PC has yielded important potentially targetable genetic alterations. Larger studies are needed to identify commonly mutated genes in advanced PC patients. Development of novel therapies targeting these cellular pathways should be considered.

Yoo SK, Song YS, Lee EK, et al.
Integrative analysis of genomic and transcriptomic characteristics associated with progression of aggressive thyroid cancer.
Nat Commun. 2019; 10(1):2764 [PubMed] Free Access to Full Article Related Publications
Anaplastic thyroid cancer (ATC) and advanced differentiated thyroid cancers (DTCs) show fatal outcomes, unlike DTCs. Here, we demonstrate mutational landscape of 27 ATCs and 86 advanced DTCs by massively-parallel DNA sequencing, and transcriptome of 13 ATCs and 12 advanced DTCs were profiled by RNA sequencing. TERT, AKT1, PIK3CA, and EIF1AX were frequently co-mutated with driver genes (BRAF

Takahashi M, Miki S, Fujimoto K, et al.
Eribulin penetrates brain tumor tissue and prolongs survival of mice harboring intracerebral glioblastoma xenografts.
Cancer Sci. 2019; 110(7):2247-2257 [PubMed] Free Access to Full Article Related Publications
Glioblastoma is one of the most devastating human malignancies for which a novel efficient treatment is urgently required. This pre-clinical study shows that eribulin, a specific inhibitor of telomerase reverse transcriptase (TERT)-RNA-dependent RNA polymerase, is an effective anticancer agent against glioblastoma. Eribulin inhibited the growth of 4 TERT promoter mutation-harboring glioblastoma cell lines in vitro at subnanomolar concentrations. In addition, it suppressed the growth of glioblastoma cells transplanted subcutaneously or intracerebrally into mice, and significantly prolonged the survival of mice harboring brain tumors at a clinically equivalent dose. A pharmacokinetics study showed that eribulin quickly penetrated brain tumors and remained at a high concentration even when it was washed away from plasma, kidney or liver 24 hours after intravenous injection. Moreover, a matrix-assisted laser desorption/ionization mass spectrometry imaging analysis revealed that intraperitoneally injected eribulin penetrated the brain tumor and was distributed evenly within the tumor mass at 1 hour after the injection whereas only very low levels of eribulin were detected in surrounding normal brain. Eribulin is an FDA-approved drug for refractory breast cancer and can be safely repositioned for treatment of glioblastoma patients. Thus, our results suggest that eribulin may serve as a novel therapeutic option for glioblastoma. Based on these data, an investigator-initiated registration-directed clinical trial to evaluate the safety and efficacy of eribulin in patients with recurrent GBM (UMIN000030359) has been initiated.

Censi S, Barollo S, Grespan E, et al.
Prognostic significance of TERT promoter and BRAF mutations in TIR-4 and TIR-5 thyroid cytology.
Eur J Endocrinol. 2019; 181(1):1-11 [PubMed] Related Publications
Objective: Follicular-derived thyroid cancers generally have a good prognosis, but in a minority of cases, they have an aggressive behavior and develop distant metastases, with an increase in the associated mortality. None of the prognostic markers currently available prior to surgery can identify such cases.
Methods: TERT promoter and BRAF gene mutations were examined in a series of 436 consecutive TIR-4 and TIR-5 nodes referred for surgery. Follow-up (median: 59 months, range: 7-293 months) was available for 384/423 patients with malignant nodes.
Results: TERT promoter and BRAF mutations were detected in 20/436 (4.6%) and 257/434 thyroid nodules (59.2%), respectively. At the end of the follow-up, 318/384 patients (82.8%) had an excellent outcome, 48/384 (12.5%) had indeterminate response or biochemical persistence, 18/384 (4.7%) had a structural persistence or died from thyroid cancer. TERT promoter mutations correlated with older age (P < 0.0001), larger tumor size (P = 0.0002), oxyntic and aggressive PTC variants (P = 0.01), higher tumor stages (P < 0.0001), distant metastases (<0.0001) and disease outcome (P < 0.0001). At multivariate analysis, TERT promoter mutation was not an independent predictor of disease outcome. TERT promoter mutation- (OR: 40.58; 95% CI: 3.06-539.04), and N1b lymph node metastases (OR: 40.16, 95% CI: 3.48-463.04) were independent predictors of distant metastases. BRAF mutation did not predict the outcome, and it correlated with a lower incidence of distant metastases (P = 0.0201).
Conclusions: TERT promoter mutation proved an independent predictor of distant metastases, giving clinicians the chance to identify many of the patients who warranted more aggressive initial treatment and closer follow-up.

Cocchiola R, Rubini E, Altieri F, et al.
STAT3 Post-Translational Modifications Drive Cellular Signaling Pathways in Prostate Cancer Cells.
Int J Mol Sci. 2019; 20(8) [PubMed] Free Access to Full Article Related Publications
STAT3 is an oncoprotein overexpressed in different types of tumors, including prostate cancer (PCa), and its activity is modulated by a variety of post-translational modifications (PTMs). Prostate cancer represents the most common cancer diagnosed in men, and each phase of tumor progression displays specific cellular conditions: inflammation is predominant in tumor's early stage, whereas oxidative stress is typical of clinically advanced PCa. The aim of this research is to assess the correspondence between the stimulus-specificity of STAT3 PTMs and definite STAT3-mediated transcriptional programs, in order to identify new suitable pharmacological targets for PCa treatment. Experiments were performed on less-aggressive LNCaP and more aggressive DU-145 cell lines, simulating inflammatory and oxidative-stress conditions. Cellular studies confirmed pY705-STAT3 as common denominator of all STAT3-mediated signaling. In addition, acK685-STAT3 was found in response to IL-6, whereas glutC328/542-STAT3 and pS727-STAT3 occurred upon tert-butyl hydroperoxyde (tBHP) treatment. Obtained results also provided evidence of an interplay between STAT3 PTMs and specific protein interactors such as P300 and APE1/Ref-1. In accordance with these outcomes, mRNA levels of STAT3-target genes seemed to follow the differing STAT3 PTMs. These results highlighted the role of STAT3 and its PTMs as drivers in the progression of PCa.

Rao S, Kanuri NN, Nimbalkar V, et al.
High frequency of H3K27M immunopositivity in adult thalamic glioblastoma.
Neuropathology. 2019; 39(2):78-84 [PubMed] Related Publications
Adult thalamic glioblastomas (GBM) are uncommon tumors with limited available molecular data. One of the reported molecular alterations in these tumors is the H3K27M mutation. It has been documented that H3K27M mutation is found in a high proportion of pediatric thalamic gliomas. In this study, we have analyzed the molecular alterations exclusive to adult thalamic GBM. This is a 6 years retrospective study of adult thalamic GBM patients who underwent surgical decompression of the tumor. Clinical data were obtained from the case records. Immunohistochemistry (IHC) was performed on the tumors using antibodies directed against the gene products of R132H mutant isocitrate dehydrogenase 1 (IDH1), alpha-thalassemia/mental retardation X-linked (ATRX), p53, H3K27M, H3K27me3, and V600E mutant BRAF. Molecular analyses were carried out to detect other IDH1 and IDH2 mutations, O

Giorgenon TMV, Carrijo FT, Arruda MA, et al.
Preoperative detection of TERT promoter and BRAFV600E mutations in papillary thyroid carcinoma in high-risk thyroid nodules.
Arch Endocrinol Metab. 2019 Mar-Apr; 63(2):107-112 [PubMed] Related Publications
OBJECTIVES: This observational study analyzed telomerase reverse transcriptase (pTERT) mutations in 45 fine-needle aspiration (FNA) specimens obtained from thyroid nodules followed by postoperatively confirmation of papillary thyroid cancer (PTC) diagnosis, examining their relationship with clinicopathologic aspects and the BRAFV600E mutation.
SUBJECTS AND METHODS: Clinical information was collected from patients who presented to Ribeirao Preto University Hospital for surgical consultation regarding a thyroid nodule and who underwent molecular testing between January 2010 to October 2012. Tests included a DNA-based somatic detection of BRAFV600E and pTERT mutations.
RESULTS: We found coexistence of pTERTC228T and BRAFV600E mutations in 8.9% (4/45) of thyroid nodules. All nodules positive for pTERT mutations were BRAFV600E positives. There was a significant association between pTERTC228T/BRAFV600E with older age and advanced stage compared with the group negative for either mutation.
CONCLUSIONS: This series provides evidence that FNA is a reliable method for preoperative diagnosis of high-risk thyroid nodules. pTERTC228T/BRAFV600E mutations could be a marker of poor prognosis. Its use as a personalized molecular medicine tool to individualize treatment decisions and follow-up design needs to be further studied.

Longerich T, Endris V, Neumann O, et al.
Gut. 2019; 68(7):1287-1296 [PubMed] Related Publications
OBJECTIVE: We aimed at the identification of genetic alterations that may functionally substitute for
DESIGN: Large cohorts of HCA (n=185) and HCC (n=468) were classified using immunohistochemistry. The mutational status of the

Hayashi Y, Fujita K, Matsuzaki K, et al.
Diagnostic potential of TERT promoter and FGFR3 mutations in urinary cell-free DNA in upper tract urothelial carcinoma.
Cancer Sci. 2019; 110(5):1771-1779 [PubMed] Free Access to Full Article Related Publications
Most upper tract urothelial carcinomas (UTUC) are muscle invasive at the time of diagnosis. Current standard methods for the diagnosis of UTUC are invasive. Urine cytology is the only non-invasive test for detecting UTUC, but its sensitivity is low. A novel non-invasive assay for UTUC detection would improve patient outcome. This study aimed to investigate the mutation of cell-free DNA (cfDNA) in urine supernatant to develop a reliable diagnostic biomarker for UTUC patients. We studied urinary cfDNA from 153 individuals, including 56 patients with localized UTUC, and carried out droplet digital PCR assay for TERT promoter and FGFR3 hotspot mutations. We could detect mutations of TERT C228T in 22/56 (39.3%), TERT C250T in 4/56 (7.1%), and FGFR3 S249C in 9/56 (16.1%) patients. FGFR3 mutation was detected only in ≤pT1 tumors (positive predictive value: 100.0%). In combination with cytology results, the sensitivity was 78.6%, and the specificity was 96.0%. Although these data need to be validated in a larger-scale cohort, mutation analysis of TERT promoter and FGFR3 in urinary cfDNA has the potential to be a non-invasive diagnostic marker and reliable factor for tumor staging.

Wang F, Cheng Y, Zhang C, et al.
A novel antisense oligonucleotide anchored on the intronic splicing enhancer of hTERT pre-mRNA inhibits telomerase activity and induces apoptosis in glioma cells.
J Neurooncol. 2019; 143(1):57-68 [PubMed] Related Publications
INTRODUCTION: Alternative splicing of hTERT pre-mRNA is an important step in the regulation of telomerase activity, but the regulation mechanisms and functions remain unclear.
METHODS: RT-PCR analysis was used to detect hTERT splicing in glioma cell lines and brain tissues. TRAP assay was used to detect the telomerase activity. Then, we designed and synthesized 2'-O-methyl-RNA phosphorothioate AONs and transfected them into glioma cells to detect the changes in telomerase activity. MTT assay, plate colony formation assay, western blotting and Annexin V/PI assay were used to detect cell proliferation and apoptosis. At last, bioinformatics analyses were used to predict the expression and function of splicing protein SRSF2 in gliomas.
RESULTS: hTERT splicing occurs both in glioma cell lines and glioma patients' tissues. The telomerase activity was related to the expression level of the full-length hTERT, rather than the total hTERT transcript level. AON-Ex726 was complementary to the sequence of the intronic splicing enhancer (ISE) in intron six, and significantly altered the splicing pattern of hTERT pre-mRNA, reducing the expression level of the full-length hTERT mRNA and increasing the expression level of the -β hTERT mRNA. After transfection with AON-Ex726, the level of apoptosis was increased, while telomerase activity and cell proliferation were significantly decreased. By bioinformatic predictions, we found the AON-Ex726 anchoring sequence in ISE overlaps the binding site of SRSF2 protein, which is up-regulated during the development of gliomas.
CONCLUSIONS: Our findings provided new targets and important clues for the gene therapy of gliomas by regulating the alternative splicing pattern of hTERT pre-mRNA.

Camargo Barros-Filho M, Barreto Menezes de Lima L, Bisarro Dos Reis M, et al.
Int J Mol Sci. 2019; 20(6) [PubMed] Free Access to Full Article Related Publications
Despite the low mortality rates, well-differentiated thyroid carcinomas (WDTC) frequently relapse.

Singh V, Singh AP, Sharma I, et al.
Epigenetic deregulations of Wnt/β-catenin and transforming growth factor beta-Smad pathways in esophageal cancer: Outcome of DNA methylation.
J Cancer Res Ther. 2019 Jan-Mar; 15(1):192-203 [PubMed] Related Publications
Background: Promoter methylation of tumor suppressor genes (TSGs) is a well-reported portent in carcinogenesis; hence, it is worthy to investigate this in high-risk Northeast population of India. The study was designed to investigate methylation status of 94 TSGs in esophageal squamous cell carcinoma (ESCC). Further, the effect of OPCML promoter methylation on gene expression was analyzed by immunohistochemistry. Moreover, in silico protein-protein interactions were examined among 8 TSGs identified in the present study and 23 epigenetically regulated genes reported previously by our group in ESCC.
Materials and Methods: Methylation profiling was carried out by polymerase chain reaction array and OPCML protein expression was examined by tissue microarray-based immunohistochemistry.
Results: OPCML, NEUROG1, TERT, and WT1 genes were found hypermethylated and SCGB3A1, CDH1, THBS1, and VEGFA were hypomethylated in Grade 2 tumor. No significant change in OPCML expression was observed among control, Grade 1, and Grade 2 tumor. Conclusively, hypermethylation of the studied OPCML promoter in Grade 2 tumor produced no effect on expression. Unexpectedly, OPCML expression was downregulated in Grade 3 tumor in comparison to other groups signifying that downregulation of OPCML expression may lead to higher grade of tumor formation at the time of diagnosis of ESCC in patients. Significant interactions at protein level were found as VEGFA:PTK2, CTNNB1:CDH1, CTNNB1:VEGFA, CTNNB1:NEUROG1, CTNND2:CDH1, and CTNNB1:TERT. These interactions are pertinent to Wnt/β-catenin and TGF-β-Smad pathways.
Conclusions: Deranged OPCML expression may lead to high-grade ESCC as well as epigenetically regulated genes, that is, CDH1, CTNNB1, CTNND2, THBS1, PTK2, WT1, OPCML, TGFB1, and SMAD4 may alter the Wnt/β-catenin and TGF-β-Smad pathways in ESCC. Further study of these genes could be useful to understand the molecular pathology of ESCC with respect to epithelial-mesenchymal transition (EMT) mediated by Wnt/β-catenin and TGF-β signaling pathways.

Demicco EG
Molecular updates in adipocytic neoplasms
Semin Diagn Pathol. 2019; 36(2):85-94 [PubMed] Related Publications
Adipocytic neoplasms include a diversity of both benign tumors (lipomas) and malignancies (liposarcomas), and each tumor type is characterized by its own unique molecular alterations driving tumorigenesis. Work over the past 30 years has established the diagnostic utility of several of these characteristic molecular alterations (e.g. MDM2 amplification in well- and dedifferentiated liposarcoma, FUS/EWSR1-DDIT3 gene fusions in myxoid liposarcoma, RB1 loss in spindle cell/pleomorphic lipoma). More recent studies have focused on additional molecular alterations which may have therapeutic or prognostic impact. This review will summarize several of the important molecular findings in adipocytic tumors that have been described over the past 10 years.

Wazir U, Orakzai MMAW, Martin TA, et al.
Correlation of
Cancer Genomics Proteomics. 2019 Mar-Apr; 16(2):121-127 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Telomerase reverse transcriptase (TERT) has a well-known role in carcinogenesis due to its functions in inducing cell immortality and preventing senescence. In this study, the relationships between TERT and a panel of known stem cell markers was examined in order to direct future enquiries into the role of 'stem-ness' in human breast cancer.
MATERIALS AND METHODS: Breast cancer tissues (n=124) and adjacent normal tissues (n=30) underwent reverse transcription and quantitative polymerase chain reaction. Transcript levels were analyzed for the correlation with that of TERT.
RESULTS: A significant direct correlation was found in cancerous tissue between TERT and BMI1 proto-oncogene polycomb ring finger 4 (BMI1; n=88, p<0.001), nestin (NES; n=88, p<0.001), POU domain, class 5, transcription factor 1 (POU5F1; n=88, p<0.001), aldehyde dehydrogenase 1 family member A2 (ALDH1A2; n=87, p=0.0298), cyclin-dependent kinase inhibitor 1A (CDKN1A; n=88, p<0.001), integrin subunit beta 1 (ITGNB1; n=88, p<0.001), integrin subunit alpha 6 (ITGA6; n=88, p<0.001), cluster of differentiation antigen 24 (CD24; n=88, p=0.0114), MET proto-oncogene (MET; n=78, p<0.001) and noggin (NOG; n=88, p<0.001).
CONCLUSION: The evidence presented in this article of possible interactions between TERT and a discrete subset of known stem cell markers would significantly contribute to further enquiries regarding clonal dynamics in the context of human breast cancer.

Lee MJ, Tsai YJ, Lin MY, et al.
Calebin-A induced death of malignant peripheral nerve sheath tumor cells by activation of histone acetyltransferase.
Phytomedicine. 2019; 57:377-384 [PubMed] Related Publications
BACKGROUND: Neurofibromatosis type 1 (NF1) is one of the most common hereditary neurocutaneous disorders. The malignant peripheral nerve sheath tumor (MPNST), transformed from NF1 related plexiform neurofibroma, is a rapidly growing and highly invasive tumor. No effective chemotherapeutic agent is currently available. Calebin-A is a derivative from turmeric Curcuma longa. Given the anti-inflammatory and anticancer potentials of curcumin, whether Calebin-A also had the tumoricidal effect upon MPNST cells is still elusive.
PURPOSE: To determine whether Calebin-A has the potential for anti-MPNST effect.
METHODS: The MTT and FACS analysis of normal Schwann (HSC) and MPNST cells have been employed to determine the tumoricidal effect of Calebin-A. The expression of the signal pathway molecules was assessed by Western blotting. The CHIP with quantitative PCR assay was performed to quantify the promoter DNA binding to acetylated histone 3 (acetyl H3). The enzyme activities of histone acetyltransferase (HAT) and deacetylase (HDAC) have been evaluated by commercial kits. The measurements of tumor size of the xenograft mouse model were also performed.
RESULTS: Calebin-A inhibited the proliferation of MPNST and primary neurofibroma cells in a dose-dependent manner. The flow cytometry analysis of the MPNST cells after treatment of 25 μm of Calebin-A demonstrated an increase of population in the G0/G1 phase but decrease in G2/M phase. Before treatment, the expression of Axl, Tyro3, and acetyl H3 was significantly higher in MPNST cells when compared to HSC. The expression of phosphorylated-AKT, -ERK1/2, survivin, hTERT, and acetyl H3 proteins were reduced after treatment. The CHIP assay shows the promoter DNA copies of survivin (BRIC5) and hTERT genes are significantly reduced post-treatment. The enzyme activity of HAT was significantly reduced, but not that of HDAC. Two HAT inhibitors, epigallocatechin-3-gallate (EGCG) and anacardic acid (AA) have also demonstrated a significant inhibitory effect on MPNST cells. Finally, the measurements of tumor size showed a significant reduction of the xenograft tumors after treatment of Calebin-A.
CONCLUSION: Both in vitro and in vivo studies showed Calebin-A could inhibit the proliferation of MPNST with suppression of survivin and hTERT. The reduced expression of these two factors might be through the epigenetic histone modification resulting from the decreased activity of HAT.

Minasi S, Baldi C, Pietsch T, et al.
Telomere elongation via alternative lengthening of telomeres (ALT) and telomerase activation in primary metastatic medulloblastoma of childhood.
J Neurooncol. 2019; 142(3):435-444 [PubMed] Related Publications
PURPOSE: Elongation of telomeres is necessary for tumor cell immortalization and senescence escape; neoplastic cells use to alternative pathways to elongate telomeres: telomerase reactivation or a telomerase-independent mechanism termed alternative lengthening of telomeres (ALT). Telomerase and ALT pathway has been explored in adult and pediatric gliomas and medulloblastomas (MDBs); however, these mechanisms were not previously investigated in MDBs metastatic at the onset. Therefore, we analyzed the activation of telomerase and ALT pathway in a homogenous cohort of 43 pediatric metastatic medulloblastomas, to investigate whether telomere elongation could play a role in the biology of metastatic MDB.
METHODS: We evaluated telomeres length via telomere-specific fluorescence in situ hybridization (Telo-FISH); we assessed nuclear expression of ATRX by immunohistochemistry (IHC). H3F3A and TERT promoter mutations were analyzed by pyrosequencing, while UTSS methylation status was analyzed via methylation-specific-PCR (MS-PCR).
RESULTS: H3F3A mutations were absent in all MDBs, 30% of samples showed ATRX nuclear loss, 18.2% of cases were characterized by TERT promoter mutations, while 60.9% harboured TERT promoter hyper-methylation in the UTSS region. Elongation of telomeres was found in 42.8% of cases. Metastatic MDBs control telomere elongation via telomerase activation (10.7%), induced by TERT promoter mutations in association with UTSS hyper-methylation, and ALT mechanism (32.1%), triggered by ATRX inactivation. Among non-metastatic MDBs, only 5.9% (1/17) showed ATRX nuclear loss with activation of ALT.
CONCLUSIONS: Our metastatic cases frequently activate ALT pathway, suggesting that it is a common process for senescence escape in primary metastatic medulloblastomas. Furthermore, the activation of mechanisms for telomere elongation is not restricted to certain molecular subgroups in this high-risk group of MDBs.

Zhou R, Shi C, Tao W, et al.
Analysis of Mucosal Melanoma Whole-Genome Landscapes Reveals Clinically Relevant Genomic Aberrations.
Clin Cancer Res. 2019; 25(12):3548-3560 [PubMed] Related Publications
PURPOSE: Unlike advances in the genomics-driven precision treatment of cutaneous melanomas, the current poor understanding of the molecular basis of mucosal melanomas (MM) has hindered such progress for MM patients. Thus, we sought to characterize the genomic landscape of MM to identify genomic alterations with prognostic and/or therapeutic implications.
EXPERIMENTAL DESIGN: Whole-genome sequencing (WGS) was performed on 65 MM samples, including 63 paired tumor blood samples and 2 matched lymph node metastases, with a further droplet digital PCR-based validation study of an independent MM cohort (
RESULTS: Besides the identification of well-recognized driver mutations of
CONCLUSIONS: Our largest-to-date cohort WGS analysis of MMs defines the genomic landscape of this deadly cancer at unprecedented resolution and identifies genomic aberrations that could facilitate the delivery of precision cancer treatments.

Shay JW, Wright WE
Telomeres and telomerase: three decades of progress.
Nat Rev Genet. 2019; 20(5):299-309 [PubMed] Related Publications
Many recent advances have emerged in the telomere and telomerase fields. This Timeline article highlights the key advances that have expanded our views on the mechanistic underpinnings of telomeres and telomerase and their roles in ageing and disease. Three decades ago, the classic view was that telomeres protected the natural ends of linear chromosomes and that telomerase was a specific telomere-terminal transferase necessary for the replication of chromosome ends in single-celled organisms. While this concept is still correct, many diverse fields associated with telomeres and telomerase have substantially matured. These areas include the discovery of most of the key molecular components of telomerase, implications for limits to cellular replication, identification and characterization of human genetic disorders that result in premature telomere shortening, the concept that inhibiting telomerase might be a successful therapeutic strategy and roles for telomeres in regulating gene expression. We discuss progress in these areas and conclude with challenges and unanswered questions in the field.

Yadav SS, Kumar M, Varshney A, Yadava PK
KLF4 sensitizes the colon cancer cell HCT-15 to cisplatin by altering the expression of HMGB1 and hTERT.
Life Sci. 2019; 220:169-176 [PubMed] Related Publications
AIMS: Insensitivity of cancer cells to therapeutic drugs is the most daunting challenge in cancer treatment. The mechanism of developing chemo-resistance is only partly understood to date. In continuation of some earlier reports, we hypothesize that KLF4, a key transcription factors that also has a crucial role in maintaining the stemness in cancer cells, may offer a basis for chemo-resistance.
MAIN METHODS: Sensitivity of cells to cisplatin was analyzed by cell proliferation, colony formation, and cell growth assay. Cell cycle analysis and immunophenotyping were used to measure cell cycle arrest and level of reactive oxygen species respectively. Immunoblotting was used to analyze the change in expression hTERT and HMGB1 involved in KLF4 mediated cisplatin resistance.
KEY FINDINGS: We found that KLF4 expression sensitizes cancer cell to cisplatin cytotoxicity. Further, KLF4 promotes the cisplatin-mediated G2/M cell cycle arrest while KLF4 knocked down induces cisplatin-mediated S-phase arrest compared to control. Decreased level of reactive oxygen species (ROS) in cisplatin-treated and KLF4 knocked down HCT-15 cells compared to vector control, accounting for increased cell survival. Immuno-blotting showed that KLF4 positively regulates expression of the survival proteins hTERT and HMGB1 while in presence of cisplatin, expression of HMGB1 and hTERT is negatively regulated by KLF4.
SIGNIFICANCE: This study suggests the involvement of KLF4-HMGB1/hTERT signaling in offering the basis for chemo-resistance in colon cancer cells and KLF4 overexpression as a probable strategy for sensitizing drug-resistant cancer cells to chemotherapy. The present study opens up new avenues for cancer research and therapeutics.

Na K, Kim HS, Shim HS, et al.
Targeted next-generation sequencing panel (TruSight Tumor 170) in diffuse glioma: a single institutional experience of 135 cases.
J Neurooncol. 2019; 142(3):445-454 [PubMed] Related Publications
PURPOSE: The TruSight Tumor 170 (TST-170) panel consists of a DNA workflow for the identification of single-nucleotide variants, small insertions and deletions, and copy number variation, as well as a panel of 55 genes for a RNA workflow for the identification of splice variants and gene fusions. To date, the application of TST-170 in diffuse gliomas (DGs) has not been described.
METHODS: We analyzed 135 samples of DG, which were diagnosed by WHO criteria based on histological features and conventional molecular tests including immunostaining, 1p/19q FISH, and analysis of MGMT methylation and TERT promoter mutation.
RESULTS: A total of 135 cases consisted of 38 IDH-mutant [17 astrocytoma (AC), 13 oligodendroglioma (OD) and eight glioblastoma (GBM)], 87 IDH-wildtype (six AC, three OD and 78 GBM), and 10 diffuse midline glioma, H3K27M-mutant. DNA analysis enabled the detection of all mutations identified in these samples by conventional techniques, and the results were highly comparable to the known mutations in each subtype. RNA analysis detected four fusion genes including PTPRZ1-MET, FGFR3-TACC3, FAM131B-BRAF, and RET-CCDC6 and one splicing variant (EGFR vIII mutant). Clustered copy number loss in 1p and 19q loci genes were detected in 1p/19q-codeleted OD.
CONCLUSIONS: The application of TST-170 panel based NGS in clinical and laboratory setting is expected to improve diagnostic accuracy and prognostication. Most benefits are expected in IDH-wildtype DG, a group of genetically heterogenous tumors harboring DNA sequence changes, copy number alterations, and fusions in a large number of oncogenes and tumor suppressor genes.

Colebatch AJ, Dobrovic A, Cooper WA
J Clin Pathol. 2019; 72(4):281-284 [PubMed] Related Publications
In this review, we summarise the function and structure of telomerase reverse transcriptase (

Okamoto M, Soeda T, Asamura A, et al.
Functional comparison of the human epidermal growth factor receptor and telomerase reverse transcriptase promoters in canine tumor cells.
J Vet Med Sci. 2019; 81(3):397-400 [PubMed] Free Access to Full Article Related Publications
We previously showed that the promoter region of the human epidermal growth factor receptor (hEGFR) gene elicits high transduction efficiency, with transgene expression restricted to canine breast tumor cells. However, it was unclear whether this promoter induces tumor cell-specific transgene expression in canine urothelial carcinoma cells. Furthermore, compared with studies in human cancer cells, the utility of the telomerase reverse transcriptase (TERT) gene promoter for therapeutic transgene expression in canine cancer cells has not been evaluated thus far. Here, we compared the activity of these promoters in canine mammary tumor and urothelial carcinoma cells. Our results showed that compared with the TERT promoter, the hEGFR promoter was more useful as a tumor-specific promoter to induce efficient transgene expression in canine tumor cells.

Wu YF, Ou CC, Chien PJ, et al.
Chidamide-induced ROS accumulation and miR-129-3p-dependent cell cycle arrest in non-small lung cancer cells.
Phytomedicine. 2019; 56:94-102 [PubMed] Related Publications
BACKGROUND: Epigenetic therapy is a promising popular treatment modality for various cancers. Histone modification and miRNA should not be underestimated in lung cancer. This study aimed to investigate whether chidamide, a histone deacetylase inhibitor (HDACi), which inhibits telomerase activity and induces cell cycle arrest, influences ROS and miRNA production in non-small cell lung cancer (NSCLC) cells.
METHODS: H1355 and A549 were treated with chidamide. The analysis of DNA content was measured by FACSCalibur equipped with a 488 nm laser. H1355 cells were transfected with miR-129-3p mimic by Lipofectamine2000. Telomerase activity was performed on the telomeric repeat amplification protocol (TRAP) assay. Detection of thymidylate synthase (TS), p21, p53, pRB, and β-actin, were performed by western blot analysis.
RESULTS: Our data showed that expression of TS, p21, and pRB were altered in the presence of chidamide by PCR and western blot. Using BrdU-incorporation analysis, we found that chidamide induced G1 arrest through the regulation of the TS gene by miR-129-3p. Chidamide was shown to suppress telomerase activity in the TRAP assay and reduced the expression of human telomerase reverse transcriptase (hTERT) by PCR and q-PCR in H1355 and A549 cells. Chidamide increased the generation of reactive oxygen species (ROS) by flow cytometry. N-acetyl cysteine (NAC), a ROS scavenger, attenuated chidamide-induced telomerase activity inhibition.
CONCLUSION: Chidamide repressed telomerase activity through ROS accumulation and cell cycle arrest by miR-129-3p upregulation in both H1355 and A549 cells. This is the first study to demonstrate that chidamide induces miR-129-3p upregulation and ROS accumulation, leading to cell cycle arrest.

Martins-Filho SN, Alves VAF, Wakamatsu A, et al.
A phenotypical map of disseminated hepatocellular carcinoma suggests clonal constraints in metastatic sites.
Histopathology. 2019; 74(5):718-730 [PubMed] Related Publications
AIMS: Access to tissue in patients with hepatocellular carcinoma (HCC) is limited compared to other malignancies, particularly at advanced stages. This has precluded a thorough characterisation of molecular drivers of HCC dissemination, particularly in relation to distant metastases. Biomarker assessment is restricted to early stages, and paired primary-metastatic comparisons between samples from the same patient are difficult.
METHODS AND RESULTS: We report the evaluation of 88 patients with HCC who underwent autopsy, including multiregional sampling of primary and metastatic sites totalling 230 nodules analysed. The study included morphological assessment, immunohistochemistry and mutation status of the TERT promoter, the most frequently mutated gene in HCC. We confirm a strong predilection of HCC for lung dissemination, including subclinical micrometastases (unrecognised during imaging and macroscopic examinations) in 30% of patients with disseminated disease. Size of dominant tumour nodule; multinodularity; macrovascular invasion; high histological, nuclear and architectural grades; and cellular crowding were associated with the presence of extrahepatic metastasis. Among the immunohistochemistry markers tested, metastatic nodules had significantly higher K19 and EpCAM expression than primary liver tumours. Morphological and immunohistochemical features showed that metastatic HCC could be traced back to the primary tumour, sometimes to a specific hepatic nodule.
CONCLUSIONS: This study suggests limited heterogeneity in metastatic sites compared to primary tumour sites.

Trifunovic J, Basta Jovanovic G, Nikolic N, et al.
HTERT promoter methylation and single nucleotide polymorphism (-245 T>C) affect renal cell carcinoma behavior in Serbian population.
J BUON. 2018 Nov-Dec; 23(6):1887-1892 [PubMed] Related Publications
PURPOSE: Renal cell carcinoma (RCC) is the most common renal cancer in adults and includes several subtypes that may be distinguished by their histology, genetic background, clinical course and responses to treatment. Human telomerase reverse transcriptase (hTERT), a crucial enzyme for telomere maintenance, has been linked to RCC development. The purpose of this study was to search for genetic and epigenetic alterations in hTERT (promoter mutations and methylation and gene amplification), and to establish a possible association between molecular and clinico-pathological characteristics of RCC.
METHODS: DNA was extracted from 31 formalin-fixed, paraffin-embedded tumor samples and 23 blood samples from 54 patients with RCC. Polymerase chain reaction (PCR) products were sequenced and analyzed using the Sequencher software. HTERT amplification was determined by quantitative PCR, while the promoter methylation status was assessed by methylation specific PCR. Statistical analysis was performed using SPSS.
RESULTS: No mutations could be detected in the hTERT promoter but only a single nucleotide polymorphism (SNP) (-245 T>C). In 54 analyzed RCC cases, the variant allele C was present in homozygous or heterozygous form in 48% of the patients. The C allele was significantly more frequent in low grade tumors (p=0.046). Gene amplification was detected in 19.4% of the 31 RCCs and hTERT methylation in 54.8% of the 31 samples. An association was established between methylation and histological type of RCC (p=0.047).
CONCLUSIONS: HTERT seems to be implicated in RCC pathogenesis since the promoter polymorphism exerts a modulation effect on tumor behavior. In addition, hTERT promoter methylation status is related to RCC histology.

Akbarzadeh M, Majidinia M, Fekri Aval S, et al.
Molecular Targeting of Notch Signaling Pathway by DAPT in Human Ovarian Cancer: Possible Anti Metastatic Effects
Asian Pac J Cancer Prev. 2018; 19(12):3473-3477 [PubMed] Free Access to Full Article Related Publications
Background: Ovarian cancer is one of the most important gynecological malignancies, causing significant mortality. Recently, there has been extensive attention to the involvement of signaling cascades in its initiation/progression. In this study, we focused on the possible role of Notch signal transduction in proliferation and metalloproteinase 2 and 9 function in human ovarian cancer OVCAR-3 cells. Methods: MTT proliferation assays were used to evaluate effects of a DAPT inhibitor on cell proliferation. For measurement of Hes-1 mRNA levels, quantitative reverse transcription polymerase chain reaction (qRT-PCR) was applied following 48 h incubation with the inhibitor. In addition, metalloproteinase (MMPs) activity was assessed by zymography. Results: Inhibition of Notch signaling resulted in a significant reduction in OVCAR-3 cell proliferation. Additionally, DAPT treatment of cells significantly decreased Hes-1 mRNA levels (p < 0.05) as well as activity of MMP-2 and -9 (p < 0.05). Conclusion: Our results suggested that suppression of Notch signaling by a specific inhibitor can effectively decrease proliferation and the potential for metastasis of OVCAR-3 cells via a reduction in the activity of metalloproteinases 2 and 9. Thus, pharmacological targeting of the Notch signaling pathway could be a promising future treatment for ovarian cancer.

Sayed ME, Yuan L, Robin JD, et al.
NOVA1 directs PTBP1 to hTERT pre-mRNA and promotes telomerase activity in cancer cells.
Oncogene. 2019; 38(16):2937-2952 [PubMed] Free Access to Full Article Related Publications
Alternative splicing is dysregulated in cancer cells, driving the production of isoforms that allow tumor cells to survive and continuously proliferate. Part of the reactivation of telomerase involves the splicing of hTERT transcripts to produce full-length (FL) TERT. Very few splicing factors to date have been described to interact with hTERT and promote the production of FL TERT. We recently described one such splicing factor, NOVA1, that acts as an enhancer of FL hTERT splicing, increases telomerase activity, and promotes telomere maintenance in cancer cells. NOVA1 is expressed primarily in neurons and is involved in neurogenesis. In the present studies, we describe that polypyrimidine-tract binding proteins (PTBPs), which are also typically involved in neurogenesis, are also participating in the splicing of hTERT to FL in cancer. Knockdown experiments of PTBP1 in cancer cells indicate that PTBP1 reduces hTERT FL splicing and telomerase activity. Stable knockdown of PTBP1 results in progressively shortened telomere length in H1299 and H920 lung cancer cells. RNA pulldown experiments reveal that PTBP1 interacts with hTERT pre-mRNA in a NOVA1 dependent fashion. Knockdown of PTBP1 increases the expression of PTBP2 which also interacts with NOVA1, potentially preventing the association of NOVA1 with hTERT pre-mRNA. These new data highlight that splicing in cancer cells is regulated by competition for splice sites and that combinations of splicing factors interact at cis regulatory sites on pre-mRNA transcripts. By employing hTERT as a model gene, we show the coordination of the splicing factors NOVA1 and PTBP1 in cancer by regulating telomerase that is expressed in the vast majority of cancer cell types.

Bagherpour M, Gharibzad K, Rassi H
Association of CDH1 and TERT Single-Nucleotide Polymorphisms with Susceptibility to Familial Breast Cancer Risk.
Monoclon Antib Immunodiagn Immunother. 2018; 37(6):239-244 [PubMed] Related Publications
Breast cancer (BC) is a multistep disease that is thought to result from an interaction between genetic background and environmental factors. In Iran, one of the strongest risk factors for developing BC is a positive family history of the disease. Recently, various polymorphisms of E-cadherin (CDH1) and TERT have been found to be associated with increased BC risk worldwide. This study aimed to analyze the association of CDH1 and TERT single-nucleotide polymorphisms with susceptibility to familial BC (FBC) risk in the Iranian patients. One hundred five patients with FBC and 110 non-FBC (NFBC) were genotyped to elucidate the potential association between CDH1 rs5030625 polymorphism and TERT rs2736098 polymorphism by polymerase chain reaction-restriction fragment length polymorphism. Then, results were evaluated by electrophoresis and Epi Info(™) 2012 software. A significant association was found between CDH1 rs5030625 GAGA genotype and FBC risk. Compared with the control group, the FBC patients had a lower frequency of GG genotype (69% vs. 85%) and a higher frequency of GAGA (5% vs. 2%, P < 0.02). Furthermore, the patients with FBC had a lower frequency of TERT rs2736098 GG genotype (38% vs. 49%, P = 0.001) and a higher frequency of rs2736098 AA genotype (12% vs. 5%, P = 0.001) compared with the NFBC. In contrast, the TERT rs2736098 GG genotype potentially increased the recurring risk of FBC (odds ratio = 3.17, P < 0.01). Allele genotypic frequencies in the FBC patients differed from those of the controls. Interestingly, tumors in FBC patients with rs2736098 GG genotype and rs5030625 GAGA exhibited higher mitotic activity, higher grade, lower estrogen receptor, and progesterone receptor than the other genotypes. In conclusion, CDH1 rs5030625 GAGA genotype and TERT rs2736098 GG genotype in combination with clinical parameters may be prognostic factors rather than susceptibility factors during the progression of FBC.

Neilsen BK, Sleightholm R, McComb R, et al.
Comprehensive genetic alteration profiling in primary and recurrent glioblastoma.
J Neurooncol. 2019; 142(1):111-118 [PubMed] Related Publications
INTRODUCTION: Glioblastoma (GBM) is heterogeneous and underlying genomic profiles influence evolution, resistance, and therapeutic responses. While extensive knowledge regarding genomic profiling of primary GBM exists, there remains a lack of understanding of genomic differences in recurrent GBM.
METHODS: We used the FoundationOne® comprehensive genomic profiling assay (CGP) to analyze ten matched primary and recurrent GBM. Genomic alterations (GA) were compared to the cancer database Catalogue of Somatic Mutations in Cancer (COSMIC).
RESULTS: All matched tumor pairs demonstrated differences in GA between the primary and recurrence including one resected without any intervening therapy. This suggests that time and/or therapeutic intervention contribute to GA. Although mutations were common to both the primary and recurrence, the percent reads varied substantially suggesting clonal expansions and contractions. For example, EGFR mutations were significantly expanded in three patients, and CNAs were increased in two patients at recurrence. Four genes that were commonly altered in both primary and recurrent GBM were more prevalent in our cohort than reported in COSMIC: CDKN2A (86% vs. 53%) and CDKN2B (86% vs. 54%) deletions, EGFR activating mutation (52% vs. 10%) or amplification (81% vs. 45%), and TERT mutation (95% vs. 51%). Lastly, PI3K pathway activating mutations were also commonly seen in our cohort (67%).
CONCLUSIONS: CGP revealed that GA identified in GBM changed over time and with treatment. Mutations in TERT, CDKN2A/CDKN2B, EGFR, and PI3K pathway were commonly observed in both primary and recurrent GBM revealing their prognostic and therapeutic potential. This may have important implications for individualized therapies and needs further evaluation.

Bayard Q, Meunier L, Peneau C, et al.
Cyclin A2/E1 activation defines a hepatocellular carcinoma subclass with a rearrangement signature of replication stress.
Nat Commun. 2018; 9(1):5235 [PubMed] Free Access to Full Article Related Publications
Cyclins A2 and E1 regulate the cell cycle by promoting S phase entry and progression. Here, we identify a hepatocellular carcinoma (HCC) subgroup exhibiting cyclin activation through various mechanisms including hepatitis B virus (HBV) and adeno-associated virus type 2 (AAV2) insertions, enhancer hijacking and recurrent CCNA2 fusions. Cyclin A2 or E1 alterations define a homogenous entity of aggressive HCC, mostly developed in non-cirrhotic patients, characterized by a transcriptional activation of E2F and ATR pathways and a high frequency of RB1 and PTEN inactivation. Cyclin-driven HCC display a unique signature of structural rearrangements with hundreds of tandem duplications and templated insertions frequently activating TERT promoter. These rearrangements, strongly enriched in early-replicated active chromatin regions, are consistent with a break-induced replication mechanism. Pan-cancer analysis reveals a similar signature in BRCA1-mutated breast and ovarian cancers. Together, this analysis reveals a new poor prognosis HCC entity and a rearrangement signature related to replication stress.

Liu X, Bishop J, Shan Y, et al.
Highly prevalent TERT promoter mutations in aggressive thyroid cancers.
Endocr Relat Cancer. 2013; 20(4):603-10 [PubMed] Free Access to Full Article Related Publications
Mutations 1 295 228 C>T and 1 295 250 C>T (termed C228T and C250T respectively), corresponding to -124 C>T and -146 C>T from the translation start site in the promoter of the telomerase reverse transcriptase (TERT) gene, have recently been reported in human cancers, but not in thyroid cancers yet. We explored these mutations in thyroid cancers by genomic sequencing of a large number of primary tumor samples. We found the C228T mutation in 0 of 85 (0.0%) benign thyroid tumors, 30 of 257 (11.7%) papillary thyroid cancers (PTC), 9 of 79 (11.4%) follicular thyroid cancers (FTC), 3 of 8 (37.5%) poorly differentiated thyroid cancers (PDTC), 23 of 54 (42.6%) anaplastic thyroid cancers (ATC), and 8 of 12 (66.7%) thyroid cancer cell lines. The C250T mutation was uncommon, but mutually exclusive with the C228T mutation, and the two mutations were collectively found in 11 of 79 (13.9%) FTC, 25 of 54 (46.3%) ATC, and 11 of 12 (91.7%) thyroid cancer cell lines. Among PTC variants, the C228T mutation was found in 4 of 13 (30.8%) tall-cell PTC (TCPTC), 23 of 187 (12.3%) conventional PTC, and 2 of 56 (3.6%) follicular variant PTC samples. No TERT mutation was found in 16 medullary thyroid cancer samples. The C228T mutation was associated with the BRAF V600E mutation in PTC, being present in 19 of 104 (18.3%) BRAF mutation-positive PTC vs 11 of 153 (7.2%) the BRAF mutation-negative PTC samples (P=0.0094). Conversely, BRAF mutation was found in 19 of 30 (63.3%) C228T mutation-positive PTC vs 85 of 227 (37.4%) C228T mutation-negative PTC samples (P=0.0094). We thus for the first time, to our knowledge, demonstrate TERT promoter mutations in thyroid cancers, that are particularly prevalent in the aggressive thyroid cancers TCPTC, PDTC, ATC and BRAF mutation-positive PTC, revealing a novel genetic background for thyroid cancers.

Landa I, Ganly I, Chan TA, et al.
Frequent somatic TERT promoter mutations in thyroid cancer: higher prevalence in advanced forms of the disease.
J Clin Endocrinol Metab. 2013; 98(9):E1562-6 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: TERT encodes the reverse transcriptase component of telomerase, which adds telomere repeats to chromosome ends, thus enabling cell replication. Telomerase activity is required for cell immortalization. Somatic TERT promoter mutations modifying key transcriptional response elements were recently reported in several cancers, such as melanomas and gliomas.
OBJECTIVES: The objectives of the study were: 1) to determine the prevalence of TERT promoter mutations C228T and C250T in different thyroid cancer histological types and cell lines; and 2) to establish the possible association of TERT mutations with mutations of BRAF, RAS, or RET/PTC.
METHODS: TERT promoter was PCR-amplified and sequenced in 42 thyroid cancer cell lines and 183 tumors: 80 papillary thyroid cancers (PTCs), 58 poorly differentiated thyroid cancers (PDTCs), 20 anaplastic thyroid cancers (ATCs), and 25 Hurthle cell cancers (HCCs).
RESULTS: TERT promoter mutations were found in 98 of 225 (44%) specimens. TERT promoters C228T and C250T were mutually exclusive. Mutations were present in 18 of 80 PTCs (22.5%), in 40 of 78 (51%) advanced thyroid cancers (ATC + PDTC) (P = 3 × 10(-4) vs PTC), and in widely invasive HCCs (4 of 17), but not in minimally invasive HCCs (0 of 8). TERT promoter mutations were seen more frequently in advanced cancers with BRAF/RAS mutations compared to those that were BRAF/RAS wild-type (ATC + PDTC, 67.3 vs 24.1%; P < 10(-4)), whereas BRAF-mutant PTCs were less likely to have TERT promoter mutations than BRAF wild-type tumors (11.8 vs 50.0%; P = .04).
CONCLUSIONS: TERT promoter mutations are highly prevalent in advanced thyroid cancers, particularly those harboring BRAF or RAS mutations, whereas PTCs with BRAF or RAS mutations are most often TERT promoter wild type. Acquisition of a TERT promoter mutation could extend survival of BRAF- or RAS-driven clones and enable accumulation of additional genetic defects leading to disease progression.

Liu X, Qu S, Liu R, et al.
TERT promoter mutations and their association with BRAF V600E mutation and aggressive clinicopathological characteristics of thyroid cancer.
J Clin Endocrinol Metab. 2014; 99(6):E1130-6 [PubMed] Free Access to Full Article Related Publications
CONTEXT: Promoter mutations chr5:1,295,228C>T and chr5:1,295,250C>T (termed C228T and C250T, respectively) in the gene for telomerase reverse transcriptase (TERT) have been reported in various cancers and need to be further investigated in thyroid cancer.
OBJECTIVE: The aim of the study was to explore TERT promoter mutations in various thyroid tumors and examine their relationship with BRAF V600E mutation, iodine intake, and clinicopathological behaviors of thyroid cancer.
DESIGN: TERT promoter and BRAF mutations were identified by sequencing genomic DNA of primary thyroid tumors from normal- and high-iodine regions in China, and clinicopathological correlation was analyzed.
RESULTS: The C228T mutation was found in 9.6% (39 of 408) of papillary thyroid cancer (PTC), C250T was found in 1.7% (7 of 408) of PTC, and they were collectively found in 11.3% (46 of 408) of PTC. C228T was found in 31.8% (7 of 22) and C250T in 4.6% (1 of 22) of follicular thyroid cancer (FTC), and they were collectively found in 36.4% (8 of 22) of FTC. No TERT mutation was found in 44 benign thyroid tumors. The two mutations occurred in 3.8% (6 of 158) of BRAF mutation-negative PTC vs 16.0% (40 of 250) of BRAF mutation-positive PTC (P = 5.87 × 10(-4)), demonstrating their association. Unlike BRAF mutation, TERT promoter mutations were not associated with high iodine intake, but they were associated with older patient age, larger tumor size, extrathyroidal invasion, and advanced stages III/IV of PTC. Coexisting TERT and BRAF mutations were even more commonly and more significantly associated with clinicopathological aggressiveness.
CONCLUSIONS: In this large cohort, we found TERT promoter mutations to be common, particularly in FTC and BRAF mutation-positive PTC, and associated with aggressive clinicopathological characteristics.

Melo M, da Rocha AG, Vinagre J, et al.
TERT promoter mutations are a major indicator of poor outcome in differentiated thyroid carcinomas.
J Clin Endocrinol Metab. 2014; 99(5):E754-65 [PubMed] Free Access to Full Article Related Publications
CONTEXT: Telomerase promoter mutations (TERT) were recently described in follicular cell-derived thyroid carcinomas (FCDTC) and seem to be more prevalent in aggressive cancers.
OBJECTIVES: We aimed to evaluate the frequency of TERT promoter mutations in thyroid lesions and to investigate the prognostic significance of such mutations in a large cohort of patients with differentiated thyroid carcinomas (DTCs).
DESIGN: This was a retrospective observational study.
SETTING AND PATIENTS: We studied 647 tumors and tumor-like lesions. A total of 469 patients with FCDTC treated and followed in five university hospitals were included. Mean follow-up (±SD) was 7.8 ± 5.8 years.
MAIN OUTCOME MEASURES: Predictive value of TERT promoter mutations for distant metastasization, disease persistence at the end of follow-up, and disease-specific mortality.
RESULTS: TERT promoter mutations were found in 7.5% of papillary carcinomas (PTCs), 17.1% of follicular carcinomas, 29.0% of poorly differentiated carcinomas, and 33.3% of anaplastic thyroid carcinomas. Patients with TERT-mutated tumors were older (P < .001) and had larger tumors (P = .002). In DTCs, TERT promoter mutations were significantly associated with distant metastases (P < .001) and higher stage (P < .001). Patients with DTC harboring TERT promoter mutations were submitted to more radioiodine treatments (P = .009) with higher cumulative dose (P = .004) and to more treatment modalities (P = .001). At the end of follow-up, patients with TERT-mutated DTCs were more prone to have persistent disease (P = .001). TERT promoter mutations were significantly associated with disease-specific mortality [in the whole FCDTC (P < .001)] in DTCs (P < .001), PTCs (P = .001), and follicular carcinomas (P < .001). After adjusting for age at diagnosis and gender, the hazard ratio was 10.35 (95% confidence interval 2.01-53.24; P = .005) in DTC and 23.81 (95% confidence interval 1.36-415.76; P = .03) in PTCs.
CONCLUSIONS: TERT promoter mutations are an indicator of clinically aggressive tumors, being correlated with worse outcome and disease-specific mortality in DTC. TERT promoter mutations have an independent prognostic value in DTC and, notably, in PTC.

Wang N, Liu T, Sofiadis A, et al.
TERT promoter mutation as an early genetic event activating telomerase in follicular thyroid adenoma (FTA) and atypical FTA.
Cancer. 2014; 120(19):2965-79 [PubMed] Related Publications
BACKGROUND: The telomerase reverse transcriptase (TERT) promoter mutations C228T and C250T have been found in many malignancies, including in thyroid carcinomas. However, it is unclear how early these mutations occur in thyroid tumorigenesis.
METHODS: The study included primary tumors from 58 patients initially diagnosed with follicular thyroid adenoma (FTA), a benign entity, 18 with atypical FTA (AFTA) having an uncertain malignant potential, and 52 with follicular thyroid carcinoma (FTC). Sanger sequencing was used to investigate the mutational status of the TERT promoter. Telomere length and TERT messenger RNA (mRNA) expression were determined using quantitative polymerase chain reaction (PCR). Telomerase activity was assessed using a Telomerase PCR enzyme-linked immunosorbent assay kit.
RESULTS: The C228T mutation was identified in 1 of 58 FTA (2%) and 3 of 18 AFTA (17%) samples. These 4 tumors all expressed TERT mRNA and telomerase activity, whereas the majority of C228T-negative adenomas lacked TERT expression (C228T versus wild-type, P = .008). The C228T mutation was associated with NRAS gene mutations (P = .016). The patient with C228T-mutated FTA later developed a scar recurrence and died of FTC, whereas none of the remaining 57 patients with FTA had recurrence. No recurrence occurred in 3 patients with AFTA who carried C228T during the follow-up period (36-285 months). Nine of the 52 FTCs (17%) exhibited the TERT mutation (8 of 9 C228T and 1 of 9 C250T), and the presence of the mutation was associated with shorter patient survival.
CONCLUSIONS: TERT promoter mutations may occur as an early genetic event in thyroid follicular tumors that have not developed malignant features on routine histopathological workup.

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