FBXW7

Gene Summary

Gene:FBXW7; F-box and WD repeat domain containing 7
Aliases: AGO, CDC4, FBW6, FBW7, hAgo, FBX30, FBXW6, SEL10, hCdc4, FBXO30, SEL-10
Location:4q31.3
Summary:This gene encodes a member of the F-box protein family which is characterized by an approximately 40 amino acid motif, the F-box. The F-box proteins constitute one of the four subunits of ubiquitin protein ligase complex called SCFs (SKP1-cullin-F-box), which function in phosphorylation-dependent ubiquitination. The F-box proteins are divided into 3 classes: Fbws containing WD-40 domains, Fbls containing leucine-rich repeats, and Fbxs containing either different protein-protein interaction modules or no recognizable motifs. The protein encoded by this gene was previously referred to as FBX30, and belongs to the Fbws class; in addition to an F-box, this protein contains 7 tandem WD40 repeats. This protein binds directly to cyclin E and probably targets cyclin E for ubiquitin-mediated degradation. Mutations in this gene are detected in ovarian and breast cancer cell lines, implicating the gene's potential role in the pathogenesis of human cancers. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Mar 2012]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:F-box/WD repeat-containing protein 7
Source:NCBIAccessed: 16 March, 2017

Ontology:

What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
Show (3)

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 16 March 2017 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 16 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (7)

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

Entity Topic PubMed Papers
Acute Lymphocytic Leukaemia (ALL)FBXW7 and Precursor T-Cell Lymphoblastic Leukemia-Lymphoma View Publications46
Colorectal CancerFBXW7 and Colorectal Cancer View Publications43
Acute Lymphocytic Leukemia (ALL), childFBXW7 and Childhood T-cell ALL View Publications27
Breast CancerFBXW7 and Breast Cancer View Publications28
Cervical CancerFBXW7 mutations in Cervical Cancer
Ojesina et al (2014) reported FBXW7 mutations in 15% of cervical carcinomas in a whole-exome sequencing analysis of 115 patients.
View Publications6
Chronic Lymphocytic LeukemiaFBXW7 mutations in CLL
In an analysis of 1160 untreated CLL patients Jeromin et al (2014) reported 2.5% of cases had FBXW7 mutations.
View Publications6
Wilms TumourFBXW7 mutations in Wilms Tumor
In a SIOP study of over 100 Wilms tumor patients, Williams et al (2010) found that FBXW7 was mutated or deleted in approximately 4% of cases including one patient with germline mutations in both FBXW7 and WT1. This study also reported MYCN amplification in 9% of cases and the authors note MYCN is a target of FBXW7-mediated ubiquitination and degradation - suggesting a common pathway is dysregulated by different mechanisms in various Wilms tumor subtypes.
View Publications2

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

Latest Publications: FBXW7 (cancer-related)

Jiang X, Li X, Wu F, et al.
Overexpression of miR-92a promotes the tumor growth of osteosarcoma by suppressing F-box and WD repeat-containing protein 7.
Gene. 2017; 606:10-16 [PubMed] Related Publications
MicroRNAs (miRNAs) have been reported to be critical players in osteosarcoma (OS). Among numerous cancer-related miRNAs, the expression level of miR-92a and its potential role in OS has not been investigated. Here, We showed that overexpression of miR-92a was identified in OS specimens and cells compared to normal bone tissues. The high level of miR-92a was correlated with high T classification and advanced clinical stages of OS patients. Notably, miR-92a highly expressing OS patients showed a notably reduced survival rate. In vitro experiments showed that loss of miR-92a inhibited U2OS cell proliferation and cell-cycle progression while induced apoptosis. In turn, its restoration facilitated MG-63 cell growth and suppressed apoptosis. Experimental nude mice showed that miR-92a silencing prohibited the in vivo growth of OS cells. Furthermore, bioinformatics software predicted that F-box and WD repeat-containing protein 7 (FBXW7) was a direct target of miR-92a. We then observed the negative regulation of miR-92a on FBXW7 expression and the direct binding between them was further verified by dual-luciferase assays in OS cells. Forced expression of FBXW7 resulted in reduced proliferation, cell cycle arrest at G1 phase and increased apoptosis in miR-92a overexpressing MG-63 cells. In summary, this study demonstrates miR-92a probably functions as a driver of tumor progression by targeting FBXW7, and highlights the potential effects of miR-92a on prognosis and treatment of OS.

Kitade S, Onoyama I, Kobayashi H, et al.
FBXW7 is involved in the acquisition of the malignant phenotype in epithelial ovarian tumors.
Cancer Sci. 2016; 107(10):1399-1405 [PubMed] Free Access to Full Article Related Publications
FBXW7 is a ubiquitin ligase that mediates ubiquitylation of oncoproteins, such as c-Myc, cyclin E, Notch and c-Jun. FBXW7 is a known tumor-suppressor gene, and mutations in FBXW7 have been reported in various human malignancies. In this study, we examined the sequences of the FBXW7 and p53 genes in 57 ovarian cancer clinical samples. Interestingly, we found no FBXW7 mutations associated with amino acid changes. We also investigated FBXW7 expression levels in 126 epithelial ovarian tumors. FBXW7 expression was negatively correlated with the malignant potential of ovarian tumors. That is to say, FBXW7 expression levels in ovarian cancer samples were significantly lower than those in borderline and benign tumors (P < 0.01). FBXW7 expression levels in serous carcinoma samples were the lowest among four major histological subtypes. In addition, p53-mutated ovarian cancer samples showed significantly lower levels of FBXW7 expression compared with p53 wild-type cancer samples (P < 0.001). DNA methylation arrays and bisulfite PCR sequencing experiments revealed that 5'-upstream regions of FBXW7 gene in p53-mutated samples were significantly higher methylated compared with those in p53 wild-type samples (P < 0.01). This data indicates that p53 mutations might suppress FBXW7 expression through DNA hypermethylation of FBXW7 5'-upstream regions. Thus, FBXW7 expression was downregulated in ovarian cancers, and was associated with p53 mutations and the DNA methylation status of the 5'-upstream regions of FBXW7.

Srivastava S, Tsongalis GJ, Kaur P
Role of microRNAs in regulation of the TNF/TNFR gene superfamily in chronic lymphocytic leukemia.
Clin Biochem. 2016; 49(16-17):1307-1310 [PubMed] Related Publications
BACKGROUND: Chronic lymphocytic leukemia (CLL) is the most common leukemia in the Western world. The biology of this disease remains elusive. In the present times, targeted molecular therapy defines the treatment. This has made understanding the elusive biology and molecular mechanisms of the disease more relevant. MicroRNAs (miRNAs) are non-encoding RNAs that play important gene-regulatory roles in neoplastic processes. As in silico studies list nearly hundreds and more target genes for each miRNA, it is of interest to see if there are genes that have already been implicated in this disease.
OBJECTIVE: The purpose of this study was to identify genes regulated by miRNAs that are independently implicated in the pathogenesis of CLL in previously published literature.
MATERIAL AND METHODS: Eight miRNAs were selected. Genes implicated in the biology of CLL in association studies and massively parallel sequence studies were selected. TargetScanHuman 6.2, a computational program that predicts target genes of miRNAs on the basis of sequence analysis, was used to link the miRNAs to genes of interest.
RESULTS: The genes targeted by miR-15a, miR-223, miR-29a, and miR181a included IL10RA, BCL2, BCL6, DDX3X, and FBXW7. The most significant link observed was that several gene members of the TNF/TNFR superfamily were targets of miR-15a, miR-29a, and miR-181a.
CONCLUSION: MiRNAs implicated in the pathogenesis of CLL regulate genes that have independently been shown to play a role in CLL. The link between miRNAs and the TNF/TNFR superfamily is especially exciting. Understanding the molecular basis of these links in future studies may pave the way for using these miRNAs as therapeutic targets in CLL.

Sun XF, Sun JP, Hou HT, et al.
MicroRNA-27b exerts an oncogenic function by targeting Fbxw7 in human hepatocellular carcinoma.
Tumour Biol. 2016; 37(11):15325-15332 [PubMed] Related Publications
Aberrant expression of microRNAs (miRNAs) plays fundamental effect on the pathogenesis of hepatocellular carcinoma (HCC). MiR-27b was previously found to play important roles in human cancers. However, its expression status, clinical significance, and biological functions in HCC remain largely unclear. The expression status of miR-27b in HCC specimens and cells were determined with qRT-PCR. MTT, 5-bromodeoxyuridine (BrdU) proliferation assays, and flow cytometry analysis were carried out to assay proliferation, cell cycle, and apoptosis. A subcutaneous model was used to evaluated the HCC tumor growth in vivo. The putative target gene of miR-27b was disclosed by TargetScan and a luciferase reporter assay. The levels of miR-27b were overexpressed in HCC. Overexpression of miR-27b was correlated with adverse prognostic features and reduced survival rate. Inhibition of miR-27b in SMMC-7721 cells remarkably suppressed proliferative ability and cell-cycle progression while enhanced apoptosis. In contrast, miR-27b overexpression resulted in prominent increased proliferation and process of cell cycle and reduced apoptosis of Hep3B cells. In vivo studies showed that knockdown of miR-27b inhibited the in vivo growth of SMMC-7721 cells in mouse xenograft model. Furthermore, we confirmed that Fbxw7 was directly regulated by miR-27b and mediated the roles of miR-27b in HCC. We suggest that miR-27b serves as an oncogenic miRNA in HCC by modulating proliferation, cell-cycle progression, and apoptosis, and its oncogenic effect is mediated by its downstream target gene, Fbxw7.

Joneja U, Vranic S, Swensen J, et al.
Comprehensive profiling of metaplastic breast carcinomas reveals frequent overexpression of programmed death-ligand 1.
J Clin Pathol. 2017; 70(3):255-259 [PubMed] Related Publications
AIMS: Metaplastic breast carcinoma (MBC) is a rare subtype of breast carcinoma less responsive to conventional chemotherapy than ductal carcinoma. In molecular terms, MBCs usually cluster with triple-negative breast cancers (TNBCs), but have a worse prognosis than TNBCs. Studies investigating MBCs for specific biomarkers of therapy response are rare and limited by the methodological approaches. The aim of the present study was to characterise MBCs on a molecular level and test programmed death-ligand 1 (PD-L1) biomarker expression in MBCs for future therapeutic interventions.
METHODS: We profiled 297 samples (MBC (n=75), TNBC (n=106), human epidermal growth factor receptor 2 (HER2)-positive breast cancers (n=32) and hormone-positive breast cancers (n=84)) by next-generation sequencing. Immunohistochemistry for PD-L1 and programmed cell death 1 (PD-1) expression was performed using automated procedures.
RESULTS: The most commonly mutated genes in MBCs included TP53 (56%) and PIK3CA (23%). Pathogenic mutations in other genes, including HRAS, FBXW7, PTEN, AKT1 and SMAD4, were rare. PD-L1 expression was detected in a significantly higher proportion of MBCs (46%) than in other subtypes (6% each in hormone-positive and HER2-positive breast cancers, and 9% in TNBC, not otherwise specified, p<0.001). PD-1-positive tumour infiltrating lymphocytes (TILs) varied greatly in MBCs.
CONCLUSIONS: Comprehensive profiling of a large cohort of this rare subtype of breast carcinoma highlighted the predominance of TP53 mutation and increased PD-L1 expression in carcinoma cells. These results can be exploited in clinical trials using immune checkpoint inhibitors.

Jiang JX, Sun CY, Tian S, et al.
Tumor suppressor Fbxw7 antagonizes WNT signaling by targeting β-catenin for degradation in pancreatic cancer.
Tumour Biol. 2016; 37(10):13893-13902 [PubMed] Related Publications
Pancreatic cancer is one of the deadliest solid malignancies associated with aberrant Wnt signaling activation. Fbxw7 mutations have been implicated in the development of pancreatic cancer, whereas the exact mechanism of this ubiquitin ligase as a tumor suppressor remains unclear in pancreatic carcinogenesis. Here, we describe that Fbxw7 is downregulated upon pancreatic cancer development. Depletion of Fbxw7 results in tumor suppression in pancreatic cancer cells, while Fbxw7 overexpression inhibits pancreatic cancer cell proliferation and invasion. Considering the negative correlation between Fbxw7 and β-catenin, we find that Fbxw7 antagonizes Wnt signaling through targeting β-catenin for its degradation. Moreover, the inhibitory effect of Fbxw7 on pancreatic cancer cell proliferation is mainly executed by the destruction of the Wnt/β-catenin signaling pathway. We also reveal that c-myc, a widely accepted target of Fbxw7, is also transcriptionally regulated by the Fbxw7/β-catenin axis in pancreatic cancer cells. Collectively, our results demonstrate that Fbxw7 is a novel regulator of Wnt/β-catenin signaling-dependent regulation of pancreatic cancer cell growth and invasion, and inactivation of Fbxw7 in pancreatic cancer tissues might be the reason for the aberrant activation of Wnt signaling.

Zhao J, Hu C, Chi J, et al.
miR-24 promotes the proliferation, migration and invasion in human tongue squamous cell carcinoma by targeting FBXW7.
Oncol Rep. 2016; 36(2):1143-9 [PubMed] Related Publications
Recent studies suggest that aberrant expression of miR-24 is linked to various human cancers, including tongue squamous cell carcinoma (TSCC). F-box and WD-40 domain protein 7 (FBXW7), a tumor-suppressor gene, is responsible for the degradation of several proto-oncogenes. However, the function and mechanism of miR-24 and FBXW7 in TSCC remains unclear. In the present study, we found that miR-24 was increased in TSCC tissues and cell lines, and that upregulation of miR-24 was associated with advanced clinical stage and a shorter overall survival of TSCC patients. Inhibition of miR-24 significantly suppressed the proliferation, migration and invasion of TSCC cells in vitro. Furthermore, miR-24 repressed FBXW7 expression by directly binding to the 3-untranslated region of FBXW7. Moreover, the suppression of FBXW7 increased the proliferation, migration and invasion of TSCC cells, and the restoration of FBXW7 substantially attenuated the oncogenic effects of miR-24. In conclusion, our results demonstrated that upregulation of miR-24 was associated with tumor progression and poor prognosis in TSCC patients, and that overexpression of miR-24 was correlated with the proliferation, migration and invasion of TSCC cells in vitro, at least partially through regulation of its functional target FBXW7. Thus, miR-24 may serve as a novel potential biomarker for the prognosis of TSCC patients.

Yeh CH, Bellon M, Pancewicz-Wojtkiewicz J, Nicot C
Oncogenic mutations in the FBXW7 gene of adult T-cell leukemia patients.
Proc Natl Acad Sci U S A. 2016; 113(24):6731-6 [PubMed] Free Access to Full Article Related Publications
Human T-cell leukemia virus type 1 (HTLV-I) is associated with adult T-cell leukemia (ATL), an aggressive lymphoproliferative disease with a dismal prognosis. We have previously described the presence of Notch1 activating mutations and constitutive Notch1 signaling in patients with acute ATL. In this study, we report a high frequency of F-box and WD repeat domain containing 7 (FBXW7)/hCDC4 mutations within the WD40 substrate-binding domain in 8 of 32 acute ATL patients (25%). Functionally, ATL FBXW7 mutants lost their ability to interact with intracellular Notch (NICD), resulting in increased protein stability and constitutive Notch1 signaling. Consistent with the loss-of-function found in ATL patients, expression of WT FBXW7 in several patient-derived ATL lines demonstrated strong tumor-suppressor activity characterized by reduced proliferation of ATL cells. Remarkably, two FBXW7 mutants, D510E and D527G, demonstrated oncogenic activity when expressed in the presence of HTLV-I Tax, mutated p53 R276H, or c-Myc F138C found in human cancers. Transforming activity was further demonstrated by the ability of the FBXW7 D510E mutant to provide IL-2-independent growth of Tax-immortalized human T cells and increase the tumor formation in a xenograft mouse model of ATL. This study suggests that FBXW7, normally a tumor suppressor, can act as an oncogene when mutated and may play an important role in the pathogenesis of ATL.

Leo F, Bartels S, Mägel L, et al.
Prognostic factors in the myoepithelial-like spindle cell type of metaplastic breast cancer.
Virchows Arch. 2016; 469(2):191-201 [PubMed] Free Access to Full Article Related Publications
Metaplastic breast carcinoma (MBC) comprises a heterogeneous group of tumors with difficult to predict biological behavior. A subset of MBC, characterized by spindle-shaped tumor cells with a myoepithelial-like immunophenotype, was entered into a retrospective study (n = 42, median follow-up time 43 months). Molecular parameters (DNA sequences of mutation hot spots in AKT1, ALK, APC, BRAF, CDH1, CTNNB1, EGFR, ERBB2, FBXW7, FGFR2, FOXL2, GNAQ, GNAS, KIT, KRAS, MAP2K1, MET, MSH6, NRAS, PDGFRA, PIK3CA, PTEN, SF3B1, SMAD4, SRC, SRSF2, STK11, TP53, and U2AF1; copy numbers for EGFR, c-myc, FGFR, PLAG, c-met) were assessed. None of the patients had axillary lymph node involvement. In 13 cases, local recurrence developed after surgery (30.9 %). Distant metastasis occurred in seven patients (17 %; four after local recurrence). The most frequent genetic alteration was PIK3CA mutation (50 % of cases). None of the pathological parameters (size, grade, stage, Ki-67 labeling index) was significantly associated with disease-free survival (DFS) or overall survival (OS). PIK3CA mutation, especially the H1047R type, tended to adversely affect OS. Type of resection (mastectomy vs. breast-conserving therapy, width of margins) or adjuvant radiotherapy had no influence on DFS or OS, whereas in the group treated with radio-/chemotherapy, no local recurrence or metastasis and no death occurred. We conclude that the spindle cell type of MBC with myoepithelial features exhibits a higher frequency of PIK3CA mutation than other types of metaplastic or basal-like breast cancer and may benefit from combined radio-/chemotherapy. Classical pathological parameters are not helpful in identifying the high-risk tumors among this subgroup of MBC.

Zhang Y, Peng Z, Zhao Y, Chen L
microRNA-25 Inhibits Cell Apoptosis of Human Gastric Adenocarcinoma Cell Line AGS via Regulating CCNE1 and MYC.
Med Sci Monit. 2016; 22:1415-20 [PubMed] Free Access to Full Article Related Publications
BACKGROUND Gastric carcinoma is the second leading cause of cancer death. microRNAs play vital roles in regulating expression of related oncogenes. microRNA-25 (miR-25) has been found to be up-regulated in gastric carcinoma. However, its roles in affecting cell apoptosis of gastric carcinoma and the related mechanism remain elusive. This study aimed to uncover the influences of miR-25 on gastric carcinoma cell apoptosis and the possible functional mechanisms involved. MATERIAL AND METHODS Human gastric adenocarcinoma cell line AGS was used and transfected with lentivirus containing miR-25-specifc inhibitor sponge or expression vector to analyze the effects of miR-25. RESULTS miR-25 had higher expression in AGS than in human gastric epithelial cell line GES-1 (P<0.01). Inhibition of miR-25 by its sponge in AGS cells resulted in suppressed cell viability (P<0.01) and promoted cell apoptosis (P<0.01), while overexpression of miR-25 abrogated these effects (P<0.01 and P<0.05), indicating that miR-25 can promote cell viability and inhibit cell apoptosis in AGS cells. Expression analysis of related factors by Western blot showed that inhibiting miR-25 led to the up-regulation of F-box and WD repeat domain-containing 7 (FBXW7, P<0.01) and the down-regulation of FBXW7 substrates, cyclin E1 (CCNE1, P<0.01), and v-myc avian myelocytomatosis viral oncogene homolog (MYC, P<0.001). CONCLUSIONS These results indicate that miR-25 has anti-apoptosis roles in AGS cells, possibly via inhibiting FBXW7 and thus promoting oncogenes, such as CCNE1 and MYC. This study provides basic evidence for using miR-25 as a possible therapeutic target in treating gastric carcinoma.

Takeishi S, Nakayama KI
To wake up cancer stem cells, or to let them sleep, that is the question.
Cancer Sci. 2016; 107(7):875-81 [PubMed] Free Access to Full Article Related Publications
Cancer stem cells (CSCs) generate transient-amplifying cells and thereby contribute to cancer propagation. A fuller understanding of the biological features of CSCs is expected to lead to the development of new anticancer therapies capable of eradicating this life-threatening disease. Cancer stem cells are known to maintain a non-proliferative state and to enter the cell cycle only infrequently. Given that conventional anticancer therapies preferentially target dividing cells, CSCs are resistant to such treatments, with those remaining after elimination of bulk cancer cells potentially giving rise to disease relapse and metastasis as they re-enter the cell cycle after a period of latency. Targeting of the switch between quiescence and proliferation in CSCs is therefore a potential strategy for preventing the reinitiation of malignancy, underscoring the importance of elucidation of the mechanisms by which these cells are maintained in the quiescent state. The fundamental properties of CSCs are thought to be governed cooperatively by internal molecules and cues from the external microenvironment (stem cell niche). Several such intrinsic and extrinsic regulators are responsible for the control of cell cycle progression in CSCs. In this review, we address two opposite approaches to the therapeutic targeting of CSCs - wake-up and hibernation therapies - that either promote or prevent the entry of CSCs into the cell cycle, respectively, and we discuss the potential advantages and risks of each strategy.

Zheng H, Wang Y, Tang C, et al.
TP53, PIK3CA, FBXW7 and KRAS Mutations in Esophageal Cancer Identified by Targeted Sequencing.
Cancer Genomics Proteomics. 2016 May-Jun; 13(3):231-8 [PubMed] Related Publications
BACKGROUND/AIM: Esophageal cancer (EC) is a common malignancy with significant morbidity and mortality. As individual cancers exhibit unique mutation patterns, identifying and characterizing gene mutations in EC that may serve as biomarkers might help predict patient outcome and guide treatment. Traditionally, personalized cancer DNA sequencing was impractical and expensive. Recent technological advancements have made targeted DNA sequencing more cost- and time-effective with reliable results. This technology may be useful for clinicians to direct patient treatment.
MATERIALS AND METHODS: The Ion PGM and AmpliSeq Cancer Panel was used to identify mutations at 737 hotspot loci of 45 cancer-related genes in 64 EC samples from Chinese patients.
RESULTS: Frequent mutations were found in TP53 and less frequent mutations in PIK3CA, FBXW7 and KRAS.
CONCLUSION: These results demonstrate that targeted sequencing can reliably identify mutations in individual tumors that make this technology a possibility for clinical use.

Myers AP, Filiaci VL, Zhang Y, et al.
Tumor mutational analysis of GOG248, a phase II study of temsirolimus or temsirolimus and alternating megestrol acetate and tamoxifen for advanced endometrial cancer (EC): An NRG Oncology/Gynecologic Oncology Group study.
Gynecol Oncol. 2016; 141(1):43-8 [PubMed] Free Access to Full Article Related Publications
OBJECTIVE: Rapamycin analogs have reproducible but modest efficacy in endometrial cancer (EC). Identification of molecular biomarkers that predict benefit could guide clinical development.
METHODS: Fixed primary tissue and whole blood were collected prospectively from patients enrolled on GOG 248. DNA was isolated from macro-dissected tumors and blood; next-generation sequence analysis was performed on a panel of cancer related genes. Associations between clinical outcomes [response rate (RR) 20%; progression-free survival (PFS) median 4.9months] and mutations (PTEN, PIK3CA, PIK3R1, KRAS, CTNNB1, AKT1, TSC1, TSC2, NF1, FBXW7) were explored.
RESULTS: Sequencing data was obtained from tumors of 55 of the 73 enrolled pts. Mutation rates were consistent with published reports: mutations in PTEN (45%), PIK3CA (29%), PIK3R1 (24%), K-RAS (16%), CTNNB1 (18%) were common and mutations in AKT1 (4%), TSC1 (2%), TSC2 (2%), NF1 (9%) and FBXW7 (4%) were less common. Increased PFS (HR 0.16; 95% CI 0.01-0.78) and RR (response difference 0.83; 95% CI 0.03-0.99) were noted for AKT1 mutation. An increase in PFS (HR 0.46; 95% CI 0.20-0.97) but not RR (response difference 0.00, 95% CI -0.34-0.34) was identified for CTNNB1 mutation. Both patients with TSC mutations had an objective response. There were no statistically significant associations between mutations in PIK3CA, PTEN, PIK3R1, or KRAS and PFS or RR.
CONCLUSIONS: Mutations in AKT1, TSC1 and TSC2 are rare, but may predict clinical benefit from temsirolimus. CTNNB1 mutations were associated with longer PFS on temsirolimus.

Hembree TN, Teer JK, Hakam A, Chiappori AA
Genetic Investigation of Uterine Carcinosarcoma: Case Report and Cohort Analysis.
Cancer Control. 2016; 23(1):61-6 [PubMed] Related Publications
BACKGROUND: Uterine carcinosarcoma, a rare gynecological malignancy, often presents at the advanced stage with a poor prognosis because current therapies have not improved rates of survival. Genetic characterization of this tumor may lead to novel, specifically targeted drug targets to provide better treatment options for patients with this malignancy.
METHODS: We present a case of a woman aged 61 years with uterine carcinosarcoma and retrospectively analyzed 100 study patients with uterine carcinosarcoma. From this group, 9 study patients underwent targeted sequencing of 1,321 genes.
RESULTS: All 9 study patients had at least 1 mutation in JAK2, KRAS, PIK3CA, CTNNB1, PTEN, FBXW7, TP53, and ERBB2; of these, TP53 was the most frequently mutated gene (6/9). In addition, ARID1A and KMT2C, which have been described and identified as part of a set of chromatin-remodeling genes, were also found in our analyses. From our 100-person cohort clinical analyses, study patients with stage 1 cancer had a median survival rate of 33 months (95% confidence interval, 19-109) compared with a median survival rate of 6 months (95% confidence interval, 3-12) in those with stage 4 disease.
CONCLUSIONS: Disease stage alone predicted the rate of clinical survival. Up to 50% in the study group were identified at having early stage disease (stage 1/2), indicating improved rates of overall detection compared with previously reported data. Our mutational analysis findings add to the number of tumors in which these mutations have been found and suggest that chromatin-remodeling dysregulation may play a role in the tumorigenesis of carcinosarcoma.

Xu Y, Yu J, Liu T, et al.
Loss of FBXW7 is related to the susceptibility and poor prognosis of cervical squamous carcinoma.
Biomarkers. 2016; 21(4):379-85 [PubMed] Related Publications
OBJECTIVE: To investigate the relationship between F box/WD-40 domain protein 7 (FBXW7) and cervical squamous cancer.
METHODS: We investigated the FBXW7 expression in 136 cervical squamous carcinoma cases through immunohistochemistry and Western-blot analysis to evaluate the clinical significance of FBXW7 and to elucidate the relationship of FBXW7 expression with progression-free survival (PFS) and overall survival (OS).
RESULTS: Low FBXW7 expression was associated with high histologic grade, lymphovascular space invasion and lymph node metastasis, among other parameters. Patients with low FBXW7 expression exhibited poor OS and PFS.
CONCLUSIONS: FBXW7 is related to the susceptibility and prognosis of cervical squamous carcinoma, indicating FBXW7 may be a potentially important target for the prediction of prognosis.

Bonilla X, Parmentier L, King B, et al.
Genomic analysis identifies new drivers and progression pathways in skin basal cell carcinoma.
Nat Genet. 2016; 48(4):398-406 [PubMed] Related Publications
Basal cell carcinoma (BCC) of the skin is the most common malignant neoplasm in humans. BCC is primarily driven by the Sonic Hedgehog (Hh) pathway. However, its phenotypic variation remains unexplained. Our genetic profiling of 293 BCCs found the highest mutation rate in cancer (65 mutations/Mb). Eighty-five percent of the BCCs harbored mutations in Hh pathway genes (PTCH1, 73% or SMO, 20% (P = 6.6 × 10(-8)) and SUFU, 8%) and in TP53 (61%). However, 85% of the BCCs also harbored additional driver mutations in other cancer-related genes. We observed recurrent mutations in MYCN (30%), PPP6C (15%), STK19 (10%), LATS1 (8%), ERBB2 (4%), PIK3CA (2%), and NRAS, KRAS or HRAS (2%), and loss-of-function and deleterious missense mutations were present in PTPN14 (23%), RB1 (8%) and FBXW7 (5%). Consistent with the mutational profiles, N-Myc and Hippo-YAP pathway target genes were upregulated. Functional analysis of the mutations in MYCN, PTPN14 and LATS1 suggested their potential relevance in BCC tumorigenesis.

Mlecnik B, Bindea G, Kirilovsky A, et al.
The tumor microenvironment and Immunoscore are critical determinants of dissemination to distant metastasis.
Sci Transl Med. 2016; 8(327):327ra26 [PubMed] Related Publications
Although distant metastases account for most of the deaths in cancer patients, fundamental questions regarding mechanisms that promote or inhibit metastasis remain unanswered. We show the impact of mutations, genomic instability, lymphatic and blood vascularization, and the immune contexture of the tumor microenvironment on synchronous metastases in large cohorts of colorectal cancer patients. We observed large genetic heterogeneity among primary tumors, but no major differences in chromosomal instability or key cancer-associated mutations. Similar patterns of cancer-related gene expression levels were observed between patients. No cancer-associated genes or pathways were associated with M stage. Instead, mutations of FBXW7 were associated with the absence of metastasis and correlated with increased expression of T cell proliferation and antigen presentation functions. Analyzing the tumor microenvironment, we observed two hallmarks of the metastatic process: decreased presence of lymphatic vessels and reduced immune cytotoxicity. These events could be the initiating factors driving both synchronous and metachronous metastases. Our data demonstrate the protective impact of the Immunoscore, a cytotoxic immune signature, and increased marginal lymphatic vessels, against the generation of distant metastases, regardless of genomic instability.

Asao T, Fujiwara Y, Sunami K, et al.
Medical treatment involving investigational drugs and genetic profile of thymic carcinoma.
Lung Cancer. 2016; 93:77-81 [PubMed] Related Publications
BACKGROUND: Thymic carcinoma is a rare neoplasm of the thymus, and information regarding its genetic profile and optimal medical treatment is limited. We sought to characterize the genetic profile of thymic carcinoma and to evaluate the efficacy of various medical treatments, including treatment with tyrosine kinase inhibitors (TKIs), cytotoxic agents, and immune checkpoint inhibitors.
METHODS: We retrospectively reviewed medical records of 64 consecutive patients with thymic carcinoma at the National Cancer Center Hospital between April 1973 and March 2014. We analyzed treatment course of patients who underwent medical treatment involving investigational drugs. For patients with available tissue samples, targeted sequencing of 50 cancer-related genes using next-generation sequencing was performed.
RESULTS: Thirty-six patients had received chemotherapy. Median progression-free survival in patients receiving first-line chemotherapy was 7.07 months (95% confidence interval, 5.67-8.93). Median survival time was 32.6 months (95% confidence interval, 23.2-43.4). As second- or later-line chemotherapy, a total of 13 patients were treated with 24 investigational drugs, including 8 multi-targeted TKIs, 5 cytotoxic agents, and 2 immune checkpoint inhibitors. Six (24%) of the patients treated with investigational drugs maintained disease control for at least 6 months. Tissue samples of 52 patients (81.3%) were available for targeted sequencing, consisting of 52 formalin-fixed, paraffin-embedded (FFPE) and 16 fresh frozen tissue samples. The genetic alterations of TP53, KRAS, FBXW7, and NRAS were detected in 7 patients (13.5%), and no KIT mutations were noted.
CONCLUSIONS: Multi-targeted TKIs exhibited potential clinical efficacy for previously-treated thymic carcinoma. The frequency of genetic alterations in this study was low, with no apparent relationship with the efficacy of chemotherapy.

Cao J, Ge MH, Ling ZQ
Fbxw7 Tumor Suppressor: A Vital Regulator Contributes to Human Tumorigenesis.
Medicine (Baltimore). 2016; 95(7):e2496 [PubMed] Free Access to Full Article Related Publications
Rapidly accumulating data indicate that F-box/WD repeat-containing protein 7 (Fbxw7) is one of the most frequently mutated genes in human cancers and regulates a network of crucial oncoproteins. These studies have generated important new insights into tumorigenesis and may soon enable therapies targeting the Fbxw7 pathway. We searched PubMed, Embase, and ISI Web of Science databases (1973-2015, especially recent 5 years) for articles published in the English language using the key words "Fbxw7," "Fbw7," "hCDC4," and "Sel-10," and we reviewed recent developments in the search for Fbxw7. Fbxw7 coordinates the ubiquitin-dependent proteolysis of several critical cellular regulators, thereby controlling essential processes, such as cell cycle, differentiation, and apoptosis. Fbxw7 contains 3 isoforms (Fbxw7α, Fbxw7β, and Fbxw7γ), and they are differently regulated in subtract recognition. Besides those, Fbxw7 activity is controlled at different levels, resulting in specific and tunable regulation of the abundance and activity of its substrates in a variety of human solid tumor types, including glioma malignancy, nasopharyngeal carcinoma, osteosarcoma, melanoma as well as colorectal, lung, breast, gastric, liver, pancreatic, renal, prostate, endometrial, and esophageal cancers. Fbxw7 is strongly associated with tumorigenesis, and the mechanisms and consequences of Fbxw7 deregulation in cancers may soon enable the development of novel therapeutic approaches.

Malapelle U, Pisapia P, Sgariglia R, et al.
Less frequently mutated genes in colorectal cancer: evidences from next-generation sequencing of 653 routine cases.
J Clin Pathol. 2016; 69(9):767-71 [PubMed] Free Access to Full Article Related Publications
AIMS: The incidence of RAS/RAF/PI3KA and TP53 gene mutations in colorectal cancer (CRC) is well established. Less information, however, is available on other components of the CRC genomic landscape, which are potential CRC prognostic/predictive markers.
METHODS: Following a previous validation study, ion-semiconductor next-generation sequencing (NGS) was employed to process 653 routine CRC samples by a multiplex PCR targeting 91 hotspot regions in 22 CRC significant genes.
RESULTS: A total of 796 somatic mutations in 499 (76.4%) tumours were detected. Besides RAS/RAF/PI3KA and TP53, other 12 genes showed at least one mutation including FBXW7 (6%), PTEN (2.8%), SMAD4 (2.1%), EGFR (1.2%), CTNNB1 (1.1%), AKT1 (0.9%), STK11 (0.8%), ERBB2 (0.6%), ERBB4 (0.6%), ALK (0.2%), MAP2K1 (0.2%) and NOTCH1 (0.2%).
CONCLUSIONS: In a routine diagnostic setting, NGS had the potential to generate robust and comprehensive genetic information also including less frequently mutated genes potentially relevant for prognostic assessments or for actionable treatments.

Zhang Q, Karnak D, Tan M, et al.
FBXW7 Facilitates Nonhomologous End-Joining via K63-Linked Polyubiquitylation of XRCC4.
Mol Cell. 2016; 61(3):419-33 [PubMed] Free Access to Full Article Related Publications
FBXW7 is a haploinsufficient tumor suppressor with loss-of-function mutations occurring in human cancers. FBXW7 inactivation causes genomic instability, but the mechanism remains elusive. Here we show that FBXW7 facilitates nonhomologous end-joining (NHEJ) repair and that FBXW7 depletion causes radiosensitization. In response to ionizing radiation, ATM phosphorylates FBXW7 at serine 26 to recruit it to DNA double-strand break (DSB) sites, whereas activated DNA-PKcs phosphorylates XRCC4 at serines 325/326, which promotes binding of XRCC4 to FBXW7. SCF(FBXW7) E3 ligase then promotes polyubiquitylation of XRCC4 at lysine 296 via lysine 63 linkage for enhanced association with the Ku70/80 complex to facilitate NHEJ repair. Consistent with these findings, a small-molecule inhibitor that abrogates XRCC4 polyubiquitylation reduces NHEJ repair. Our study demonstrates one mechanism by which FBXW7 contributes to genome integrity and implies that inactivated FBXW7 in human cancers could be a strategy for increasing the efficacy of radiotherapy.

Liu L, Zhao X, Zhao L, et al.
Arginine Methylation of SREBP1a via PRMT5 Promotes De Novo Lipogenesis and Tumor Growth.
Cancer Res. 2016; 76(5):1260-72 [PubMed] Related Publications
Dysregulation of the sterol regulatory element-binding transcription factors sterol regulatory element-binding protein (SREBP) and SREBF activates de novo lipogenesis to high levels in cancer cells, a critical event in driving malignant growth. In this study, we identified an important posttranslational mechanism by which SREBP1a is regulated during metabolic reprogramming in cancer cells. Mass spectrometry revealed protein arginine methyltransferase 5 (PRMT5) as a binding partner of SREBP1a that symmetrically dimethylated it on R321, thereby promoting transcriptional activity. Furthermore, PRMT5-induced methylation prevented phosphorylation of SREBP1a on S430 by GSK3β, leading to its disassociation from Fbw7 (FBXW7) and its evasion from degradation through the ubiquitin-proteasome pathway. Consequently, methylation-stabilized SREBP1a increased de novo lipogenesis and accelerated the growth of cancer cells in vivo and in vitro. Clinically, R321 symmetric dimethylation status was associated with malignant progression of human hepatocellular carcinoma, where it served as an independent risk factor of poor prognosis. By showing how PRMT5-induced methylation of SREBP1a triggers hyperactivation of lipid biosynthesis, a key event in tumorigenesis, our findings suggest a new generalized strategy to selectively attack tumor metabolism.

Ock CY, Son B, Keam B, et al.
Identification of genomic mutations associated with clinical outcomes of induction chemotherapy in patients with head and neck squamous cell carcinoma.
J Cancer Res Clin Oncol. 2016; 142(4):873-83 [PubMed] Related Publications
PURPOSE: We performed deep sequencing of target genes in head and neck squamous cell carcinoma (HNSCC) tumors to identify somatic mutations that are associated with induction chemotherapy (IC) response.
METHODS: Patients who were diagnosed with HNSCC were retrospectively identified. Patients who were treated with IC were divided into two groups: good responders and poor responders by tumor response and progression-free survival. Targeted gene sequencing for 2404 somatic mutations of 44 genes was performed on HNSCC tissues. Mutations with total coverage of <500 were excluded, and the cutoff for altered allele frequency was >10 %.
RESULTS: Of the 71 patients, 45 were treated upfront with IC. Mean total coverage was 1941 per locus, and 42.2 % of tumors had TP53 mutations. Thirty-three mutations in TP53, NOTCH3, FGFR2, FGFR3, ATM, EGFR, MET, PTEN, FBXW7, SYNE1, and SUFU were frequently altered in poor responders. Among the patients who were treated with IC, those with unfavorable genomic profiles had significantly poorer overall survival than those without unfavorable genomic profiles (hazard ratio 6.45, 95 % confidence interval 2.07-20.10, P < 0.001).
CONCLUSIONS: Comprehensive analysis of mutation frequencies identified unfavorable genomic profiles, and the patients without unfavorable genomic profiles can obtain clinical benefits from IC in patients with HNSCC.

Ali SM, Pal SK, Wang K, et al.
Comprehensive Genomic Profiling of Advanced Penile Carcinoma Suggests a High Frequency of Clinically Relevant Genomic Alterations.
Oncologist. 2016; 21(1):33-9 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Advanced penile squamous cell carcinoma (PSCC) is associated with poor survival due to the aggressiveness of the disease and lack of effective systemic therapies. Comprehensive genomic profiling (CGP) was performed to identify clinically relevant genomic alterations (CRGAs).
MATERIALS AND METHODS: DNA was extracted from 40 μm of formalin-fixed, paraffin-embedded sections in patients with advanced PSCC. CGP was performed on hybridization-captured, adaptor ligation-based libraries to a mean coverage depth of 692× for 3,769 exons of 236 cancer-related genes plus 47 introns from 19 genes frequently rearranged in cancer. CRGAs were defined as genomic alterations (GAs) linked to targeted therapies on the market or under evaluation in mechanism-driven clinical trials.
RESULTS: Twenty male patients with a median age of 60 years (range, 46-87 years) were assessed. Seventeen (85%) cases were stage IV and three cases (15%) were stage III. CGP revealed 109 GAs (5.45 per tumor), 44 of which were CRGAs (2.2 per tumor). At least one CRGA was detected in 19 (95%) cases, and the most common CRGAs were CDKN2A point mutations and homozygous deletion (40%), NOTCH1 point mutations and rearrangements (25%), PIK3CA point mutations and amplification (25%), EGFR amplification (20%), CCND1 amplification (20%), BRCA2 insertions/deletions (10%), RICTOR amplifications (10%), and FBXW7 point mutations (10%).
CONCLUSION: CGP identified CRGAs in patients with advanced PSCC, including EGFR amplification and PIK3CA alterations, which can lead to the rational administration of targeted therapy and subsequent benefit for these patients.
IMPLICATIONS FOR PRACTICE: Few treatment options exist for patients with advanced penile squamous cell carcinoma (PSCC). Outcomes are dismal with platinum-based chemotherapy, with median survival estimated at 1 year or less across multiple series. Biological studies of patients with PSCC to date have principally focused on human papillomavirus status, but few studies have elucidated molecular drivers of the disease. To this end, comprehensive genomic profiling was performed in a cohort of 20 patients with advanced PSCC. Findings of frequent mutations in CDKN2A, NOTCH1, PIK3CA, and EGFR (all in excess of 20%) point to potential therapeutic avenues. Trials of targeted therapies directed toward these mutations should be explored.

Nakayama K, Rahman MT, Rahman M, et al.
CCNE1 amplification is associated with aggressive potential in endometrioid endometrial carcinomas.
Int J Oncol. 2016; 48(2):506-16 [PubMed] Free Access to Full Article Related Publications
The clinicopathological significance of amplification was investigated of the gene encoding cyclin E (CCNE1) and we assessed whether CCNE1 was a potential target in endometrioid endometrial carcinomas. CCNE1 amplification and CCNE1 or F-box and WD repeat domain-containing 7 (FBXW7) expression in endometrial endometrioid carcinoma was assessed by immunohistochemistry and fluorescence in situ hybridization. CCNE1 knockdown by small interfering RNA (siRNA) was used to assess the CCNE1 function. The results showed that CCNE1 amplification was present in 9 (8.3%) of 108 endometrial carcinomas. CCNE1 amplification was correlated with high histological grade (Grade 3; p=0.0087) and lymphovascular space invasion (p=0.0258). No significant association was observed between CCNE1 amplification and FIGO stage (p=0.851), lymph node metastasis (p=0.078), body mass index (p=0.265), deep myometrial invasion (p=0.256), menopausal status (p=0.289) or patient age (p=0.0817). CCNE1 amplification was significantly correlated with shorter progression-free and overall survival (p=0.0081 and 0.0073, respectively). CCNE1 protein expression or loss of FBXW7 expression in endometrial endometrioid carcinoma tended to be correlated with shorter progression-free and overall survival; however, this difference was not statistically significant. Multivariate analysis showed that CCNE1 amplification was an independent prognostic factor for overall survival but not for progression-free survival (P=0.0454 and 0.2175, respectively). Profound growth inhibition was observed in siRNA-transfected cancer cells with endogenous CCNE1 overexpression compared with that in cancer cells having low CCNE1 expression. CCNE1 amplification was independent of p53, HER2, MLH1 and ARID1A expression but dependent on PTEN expression in endometrial carcinomas. These findings indicated that CCNE1 amplification was critical for the survival of endometrial endometrioid carcinomas. Furthermore, the effects of CCNE1 knockdown were dependent on the CCNE1 expression status, suggesting that CCNE1-targeted therapy may be beneficial for patients with endometrial endometrioid carcinoma having CCNE1 amplification.

Lepretre S, Touzart A, Vermeulin T, et al.
Pediatric-Like Acute Lymphoblastic Leukemia Therapy in Adults With Lymphoblastic Lymphoma: The GRAALL-LYSA LL03 Study.
J Clin Oncol. 2016; 34(6):572-80 [PubMed] Related Publications
PURPOSE: This study evaluated the efficacy of pediatric-like acute lymphoblastic leukemia (ALL) therapy in adults with lymphoblastic lymphoma (LL).
PATIENTS AND METHODS: This was a prospective phase II study in adults 18 to 59 years old with previously untreated LL. Patients were treated with an adapted pediatric-like ALL protocol, which included a corticosteroid prephase, a five-drug induction reinforced by sequential cyclophosphamide administration, dose-dense consolidation, late intensification, CNS prophylaxis, and a 2-year maintenance phase. Treatment response was assessed by computed tomography and optional positron emission tomography. Allogeneic hematopoietic stem cell transplant was offered to selected patients in first complete remission (CR) or unconfirmed CR.
RESULTS: The study enrolled 148 patients (131 with T-lineage LL [T-LL] and 17 with B-lineage LL [B-LL]). A total of 119 patients with T-LL (90.8%) and 13 with B-LL (76.5%) reached CR/unconfirmed CR, including 26 with T-LL and two with B-LL who needed a second induction salvage course. Relapse occurred in 34 patients with T-LL and four with B-LL. In patients with T-LL, 3-year event-free survival was 63.3% (95% CI, 54.2% to 71.0%), disease-free survival was 72.4% (95% CI, 63.0% to 79.7%), and overall survival was 69.2% (95% CI, 60.0% to 76.7%). Multivariate analysis identified serum lactate dehydrogenase level and the NOTCH1/FBXW7/RAS/PTEN oncogene (a four-gene oncogenetic classifier) status but not positron emission tomography or hematopoietic stem cell transplant as independent prognostic factors for outcome in T-LL.
CONCLUSION: In adults with LL, an intensive pediatric-like ALL treatment protocol was associated with a good response rate and outcome. In patients with T-LL, the four-gene oncogenetic classifier and lactate dehydrogenase level were independent prognostic indicators.

Hernández JÁ, Hernández-Sánchez M, Rodríguez-Vicente AE, et al.
A Low Frequency of Losses in 11q Chromosome Is Associated with Better Outcome and Lower Rate of Genomic Mutations in Patients with Chronic Lymphocytic Leukemia.
PLoS One. 2015; 10(11):e0143073 [PubMed] Free Access to Full Article Related Publications
To analyze the impact of the 11q deleted (11q-) cells in CLL patients on the time to first therapy (TFT) and overall survival (OS), 2,493 patients with CLL were studied. 242 patients (9.7%) had 11q-. Fluorescence in situ hybridization (FISH) studies showed a threshold of 40% of deleted cells to be optimal for showing that clinical differences in terms of TFT and OS within 11q- CLLs. In patients with ≥40% of losses in 11q (11q-H) (74%), the median TFT was 19 months compared with 44 months in CLL patients with <40% del(11q) (11q-L) (P<0.0001). In the multivariate analysis, only the presence of 11q-L, mutated IGHV status, early Binet stage and absence of extended lymphadenopathy were associated with longer TFT. Patients with 11q-H had an OS of 90 months, while in the 11q-L group the OS was not reached (P = 0.008). The absence of splenomegaly (P = 0.02), low LDH (P = 0.018) or β2M (P = 0.006), and the presence of 11q-L (P = 0.003) were associated with a longer OS. In addition, to detect the presence of mutations in the ATM, TP53, NOTCH1, SF3B1, MYD88, FBXW7, XPO1 and BIRC3 genes, a select cohort of CLL patients with losses in 11q was sequenced by next-generation sequencing of amplicons. Eighty % of CLLs with 11q- showed mutations and fewer patients with low frequencies of 11q- had mutations among genes examined (50% vs 94.1%, P = 0.023). In summary, CLL patients with <40% of 11q- had a long TFT and OS that could be associated with the presence of fewer mutated genes.

Wu WJ, Shi J, Hu G, et al.
Wnt/β-catenin signaling inhibits FBXW7 expression by upregulation of microRNA-770 in hepatocellular carcinoma.
Tumour Biol. 2016; 37(5):6045-51 [PubMed] Related Publications
FBXW7 (F-box and WD repeat domain-containing 7) is the F-box protein component of a Skp1-Cul1-F-box protein-type (SCF-type) ubiquitin ligase. Previous studies have shown that FBXW7 serves as a tumor suppressor and is frequently downregulated in many types of human neoplasms. However, the molecular mechanisms for its downregulation remain poorly understood. Hyperactivation of Wnt/β-catenin signaling pathway is viewed as crucial for tumorigenesis, including hepatocellular carcinoma (HCC). In the present study, we show that protein levels, but not message RNA, of FBXW7 were suppressed by Wnt3a treatment or transfection of a constitutively activated β-catenin in HCC cells. Besides, microRNA-770 was identified as an important downstream target of Wnt/β-catenin signaling, to inhibit FBXW7 expression through targeting its 3'-untranslated region. Thus, our results suggest a previously unknown Wnt/β catenin-miR-770-FBXW7 molecular network in the HCC development.

Postel-Vinay S, Boursin Y, Massard C, et al.
Seeking the driver in tumours with apparent normal molecular profile on comparative genomic hybridization and targeted gene panel sequencing: what is the added value of whole exome sequencing?
Ann Oncol. 2016; 27(2):344-52 [PubMed] Related Publications
BACKGROUND: Molecular tumour profiling technologies have become increasingly important in the era of precision medicine, but their routine use is limited by their accessibility, cost, and tumour material availability. It is therefore crucial to assess their relative added value to optimize the sequence and combination of such technologies.
PATIENTS AND METHODS: Within the MOSCATO-01 trial, we investigated the added value of whole exome sequencing (WES) in patients that did not present any molecular abnormality on array comparative genomic hybridization (aCGH) and targeted gene panel sequencing (TGPS) using cancer specific panels. The pathogenicity potential and actionability of mutations detected on WES was assessed.
RESULTS: Among 420 patients enrolled between December 2011 and December 2013, 283 (67%) patients were analysed for both TGPS and aCGH. The tumour sample of 25 (8.8%) of them presented a flat (or low-dynamic) aCGH profile and no pathogenic mutation on TGPS. We selected the first eligible 10 samples-corresponding to a heterogeneous cohort of different tumour types-to perform WES. This allowed identifying eight mutations of interest in two patients: FGFR3, PDGFRB, and CREBBP missense single-nucleotide variants (SNVs) in an urothelial carcinoma; FGFR2, FBXW7, TP53, and MLH1 missense SNVs as well as an ATM frameshift mutation in a squamous cell carcinoma of the tongue. The FGFR3 alteration had been previously described as an actionable activating mutation and might have resulted in treatment by an FGFR inhibitor. CREBBP and ATM alterations might also have suggested a therapeutic orientation towards epigenetic modifiers and ataxia-telangectasia and Rad3-related inhibitors, respectively.
CONCLUSION: The therapeutic added value of performing WES on tumour samples that do not harbour any genetic abnormality on TGPS and aCGH might be limited and variable according to the histotype. Alternative techniques, including RNASeq and methylome analysis, might be more informative in selected cases.

Snijders AM, Liu Y, Su L, et al.
Expression profiling reveals transcriptional regulation by Fbxw7/mTOR pathway in radiation-induced mouse thymic lymphomas.
Oncotarget. 2015; 6(42):44794-805 [PubMed] Free Access to Full Article Related Publications
The tumor suppressor gene FBXW7 is deleted and mutated in many different types of human cancers. FBXW7 primarily exerts its tumor suppressor activity by ubiquitinating different oncoproteins including mTOR. Here we used gene transcript profiling to gain a deeper understanding of the role of FBXW7 in tumor development and to determine the influence of mTOR inhibition by rapamycin on tumor transcriptome and biological functions. In comparison to tumors from p53 single heterozygous (p53+/-) mice, we find that radiation-induced thymic lymphomas from Fbxw7/p53 double heterozygous (Fbxw7+/-p53+/-) mice show significant deregulation of cholesterol metabolic processes independent of rapamycin treatment, while cell cycle related genes were upregulated in tumors from placebo treated Fbxw7+/-p53+/- mice, but not in tumors from rapamycin treated Fbxw7+/-p53+/- mice. On the other hand, tumors from rapamycin treated Fbxw7+/-p53+/- mice were enriched for genes involved in the integrated stress response, an adaptive mechanism to survive in stressful environments. Finally, we demonstrated that the Fbxw7 gene signatures identified in mouse tumors significantly overlap with FBXW7 co-expressed genes in human cancers. Importantly these common FBXW7 gene signatures between mouse and human are predictive for disease-free survival in human colon, breast and lung adenocarcinoma cancer patients. These results provide novel insights into the role of FBXW7 in tumor development and have identified a number of potential targets for therapeutic intervention.

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