Gene Summary

Gene:DLEC1; DLEC1 cilia and flagella associated protein
Aliases: F56, DLC1, DLC-1, CFAP81
Summary:The cytogenetic location of this gene is 3p21.3, and it is located in a region that is commonly deleted in a variety of malignancies. Down-regulation of this gene has been observed in several human cancers including lung, esophageal, renal tumors, and head and neck squamous cell carcinoma. In some cases, reduced expression of this gene in tumor cells is a result of aberrant promoter methylation. Several alternatively spliced transcripts have been observed that contain disrupted coding regions and likely encode nonfunctional proteins.[provided by RefSeq, Mar 2016]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:deleted in lung and esophageal cancer protein 1
Source:NCBIAccessed: 01 September, 2019


What does this gene/protein do?
DLEC1 is implicated in:
- cytoplasm
- molecular_function
- negative regulation of cell proliferation
Data from Gene Ontology via CGAP

Cancer Overview

Deletions of chromosome 3p are frequent in many different types of cancer. Researchers in Tokyo (Daigo, 1999) isolated a novel gene by large-scale sequencing of genomic DNA at 3p21.3. Using RT-PCR they found non-functional RNA transcripts in 11/30 primary non-small cell lung cancers, 3/10 primary esophageal squamous cell carcinomas, 4/14 esophageal cancer cell lines and 2/2 renal cancer cell lines. However, no alterations of the gene itself were identified. They originally designated this candidate tumour supressor gene DLC1 (NOTE: the symbol DLC1 was later assigned to the gene Deleted in Liver Cancer 1 at 8p22)

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 (7)

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

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

Latest Publications: DLEC1 (cancer-related)

Kim Y, Lee K, Jeong S, et al.
DLEC1 methylation is associated with a better clinical outcome in patients with intrahepatic cholangiocarcinoma of the small duct subtype.
Virchows Arch. 2019; 475(1):49-58 [PubMed] Related Publications
Intrahepatic cholangiocarcinoma is a complex disease with three different histologic subtypes, the large duct, small duct, and bile ductular types. In the present study, we elucidated whether the three histological subtypes have differences in their methylation profiles and developed a DNA methylation marker that might help identify a subset of ICC with a different prognosis. We screened 113 promoter CpG island loci against 10 cases of intrahepatic cholangiocarcinoma and normal cystic ducts using the MethyLight assay and selected 30 CpG island loci with cancer-associated hypermethylation. Then, we analyzed 172 intrahepatic cholangiocarcinomas for the methylation state at these 30 loci. Six loci, including DLEC1, were more frequently methylated in the bile ductular type and small duct type, whereas six loci were more frequently methylated in the large duct type. Of these 30 loci, DLEC1 methylation was found mainly in the bile ductular type and small duct type but rarely in the large duct type. DLEC1 methylation was significantly associated with a better clinical outcome in intrahepatic cholangiocarcinomas of the small duct type but not of the bile ductular type. DLEC1 methylation was an independent prognostic variable in both cancer-specific survival and recurrence-free survival. For patients with intrahepatic cholangiocarcinoma of the small duct type (n = 68), DLEC1 methylation was found in 26 (38.2%) and was associated with a better clinical outcome for both cancer-specific survival and recurrence-free survival. Our findings suggest that DLEC1 methylation can be utilized to identify a subset with a better prognosis in intrahepatic cholangiocarcinomas of the small duct type.

Yang Z, Qi W, Sun L, et al.
DNA methylation analysis of selected genes for the detection of early-stage lung cancer using circulating cell-free DNA.
Adv Clin Exp Med. 2019; 28(3):361-366 [PubMed] Related Publications
BACKGROUND: Lung cancer is still the deadliest cancer in the world, but early diagnosis cannot be achieved because of the limitations of diagnostic methods. DNA methylation has been proven to be a potentially powerful tool for cancer detection and diagnosis over the past decade.
OBJECTIVES: We explored whether free DNA methylation in plasma can be a reliable biomarker for noninvasive lung cancer detection.
MATERIAL AND METHODS: We detected the methylation of 8 genes in plasma-free DNA of patients with pulmonary space-occupying lesions using real-time quantitative methylation-specific polymerase chain reaction (QMSP). Among the 50 selected patients, 39 were confirmed using pathological analysis as having early lung cancer and 11 had an inflammatory pseudotumor.
RESULTS: The QMSP detection showed that the methylation levels of 8 genes in the patients were significantly higher than in the non-lung cancer group. The methylation level of CALCA was the highest and the methylation level of HOXA9 was the lowest. Methylation of RASSF1A, CDKN2A and DLEC1 occured only in lung cancer patients, while methylation of CALCA, CDH13, PITX2, HOXA9, and WT1 occured not only in lung cancer patients, but also in non-lung cancers. The specificity reached 95~100%, whether for a single gene or overall, but the sensitivity was relatively low for each gene. The sensitivity can reach 72% if the methylation of any of the 8 genes is positive and the overall specificity was 91%. The positive and negative predictive values were 96% and 60%, respectively.
CONCLUSIONS: Quantitative detection of DNA methylation in plasma is a potential method for early diagnosis of lung cancer.

Lin HW, Fu CF, Chang MC, et al.
CDH1, DLEC1 and SFRP5 methylation panel as a prognostic marker for advanced epithelial ovarian cancer.
Epigenomics. 2018; 10(11):1397-1413 [PubMed] Related Publications
AIM: To investigate the CDH1, DLEC1 and SFRP5 gene methylation panel for advanced epithelial ovarian carcinoma (EOC).
MATERIALS & METHODS: One hundred and seventy-seven advanced EOC specimens were evaluated by methylation-specific PCR. We also used The Cancer Genome Atlas dataset to evaluate the panel.
RESULTS: The presence of two or more methylated genes was significant in recurrence (hazard ratio [HR]: 1.91 [1.33-2.76]; p = 0.002) and death (HR: 1.96 [1.26-3.06]; p = 0.006) in our cohort. In The Cancer Genome Atlas dataset, the presence of two or three methylated genes was significant in death (HR: 1.59 [1.15-2.18]; p = 0.0047) and close to the significance level in recurrence (HR: 1.37 [0.99-1.88]; p = 0.058).
CONCLUSION: The CDH1, DLEC1 and SFRP5 methylation panel is a potential prognostic biomarker for advanced EOC.

Huang X, Wu C, Fu Y, et al.
Methylation analysis for multiple gene promoters in non-small cell lung cancers in high indoor air pollution region in China.
Bull Cancer. 2018; 105(9):746-754 [PubMed] Related Publications
AIM: The prevalence and mortality rates of lung cancer in Xuanwei, Yunnan, China, are the highest in the world. The severe indoor air pollution caused by smoky coals with high benzo (a)pyrene (BaP) and quartz levels is the main environmental factor. The aim of this study was to investigate methylation profiles of promoters in eight genes in primary non-small cell lung cancers (NSCLC) exposed to smoky coals.
MATERIALS AND METHODS: Candidate genes including CDKN2A, DLEC1, CDH1, DAPK, RUNX3, APC, WIF1 and MGMT were determined for the promoter methylation status using Nested methylation-specific PCR (nMSP) in primary 23NSCLC tissues and in circulating tumor DNA (ctDNA) isolated from 42plasma samples (9matched to tissues) as well as 10healthy plasma samples, using Sanger sequencing to verify the results.
RESULTS: Seven of the 8genes, except MGMT, had relatively high methylation frequencies ranging from 39%-74% in tissues. Moreover, methylation frequencies in five genes identified in lung cancer plasma were 45% for CDKN2A, 48% for DLEC1, 76% for CDH1, 14% for DAPK, 29% for RUNX3, with a relatively good concordance of methylation among 9 tissues and paired plasma. However, the genes from all healthy plasma showed no methylation.
CONCLUSIONS: A panel of genes including CDKN2A, DLEC1, CDH1, DAPK and RUNX3 may be used as potential epigenetic biomarkers for early lung cancer detection. CDH1 promoter methylation was associated with lung cancer metastasis in areas of air pollution from buring of smoky coals. DLEC1 and CDH1 exhibited specific high methylation frequencies, different from previous reports.

Özdemir İ, Pınarlı FG, Pınarlı FA, et al.
Epigenetic silencing of the tumor suppressor genes SPI1, PRDX2, KLF4, DLEC1, and DAPK1 in childhood and adolescent lymphomas.
Pediatr Hematol Oncol. 2018; 35(2):131-144 [PubMed] Related Publications
The aim of the study was to investigate the expression and methylation status of seven distinctive genes with tumor suppressing properties in childhood and adolescent lymphomas. A total of 96 patients with Hodgkin Lymphoma (HL, n = 41), Non-Hodgkin Lymphoma (NHL, n = 15), and reactive lymphoid hyperplasia (RLH, n = 40, as controls) are included in the research. The expression status of CDKN2A, SPI1, PRDX2, DLEC1, FOXO1, KLF4 and DAPK1 genes were measured with QPCR method after the RNA isolation from paraffin blocks of tumor tissue and cDNA conversion. DNA isolation was performed from samples with low gene expression followed by methylation PCR study specific to promoter regions of these genes. We found that SPI1, PRDX2, DLEC1, KLF4, and DAPK1 genes are significantly less expressed in patient than the control group (p = 0.0001). However, expression of CDKNA2 and FOXO1 genes in the patient and control groups were not statistically different. The methylation ratios of all genes excluding the CDKN2A and FOXO1 were significantly higher in the HL and NHL groups than the controls (p = 0.0001). We showed that SPI1, PRDX2, DLEC1, KLF4 and DAPK1 genes are epigenetically silenced via hypermethylation in the tumor tissues of children with HL and NHL. As CDKN2A gene was not expressed in both patient and control groups, we conclude that it is not specific to malignancy. As FOXO1 gene was similarly expressed in both groups, its relationship with malignancy could not be established. The epigenetically silenced genes may be candidates for biomarkers or therapeutic targets in childhood and adolescent lymphomas.

Li L, Xu J, Qiu G, et al.
Epigenomic characterization of a p53-regulated 3p22.2 tumor suppressor that inhibits STAT3 phosphorylation via protein docking and is frequently methylated in esophageal and other carcinomas.
Theranostics. 2018; 8(1):61-77 [PubMed] Free Access to Full Article Related Publications

Kordiak J, Czarnecka KH, Pastuszak-Lewandoska D, et al.
Small suitability of the DLEC1, MLH1 and TUSC4 mRNA expression analysis as potential prognostic or differentiating markers for NSCLC patients in the Polish population.
J Genet. 2017; 96(2):227-234 [PubMed] Related Publications
According to the latest data, lung cancer is one of the most common cancer worldwide, men contributing nearly 21.2% and women 8.6% of all diagnosed cancers. Late detection of tumour drastically reduces the chance for a cure. Thus, it is important to search for candidate biomarkers for screening of early stage nonsmall cell lung carcinoma (NSCLC). Tumour suppressor genes, DLEC1, TUSC4 and MLH1, localized on 3p21 are recognized to play a role in NSCLC carcinogenesis. The aim of this study was to assess the relationship between the DLEC1, TUSC4 and MLH1 mRNA expression, and clinical features of NSCLC patients, tobacco addiction, and tumour histopathological characteristics. The DLEC1, TUSC4 and MLH1 expression was analysed in lung tumour tissue samples obtained from 69 patients diagnosed with NSCLC: squamous cell carcinoma (n = 34), adenocarcinoma (n = 24), large cell carcinoma (n = 5), carcinoma adenosquamosum (n = 5). A decreased gene expression (RQ < 0.7) was observed for DLEC1 in 60.9% of tumour samples, for MLH1 in 50.7% and for TUSC4 in 26% of NSCLC samples. DLEC1 was decreased in more aggressive subtypes: large cell carcinoma and adenocarcinoma-squamous cell carcinoma. The simultaneous downregulation of two of the studied genes, DLEC1 andMLH1,was observed in 30.4% of NSCLCsamples, highlighting the importance of these two genes in lung carcinogenesis. We found no correlation between the DLEC1, TUSC4 and MLH1 gene expression and NSCLC patient characteristics (gender, age and smoking) or cancer histopathology. No significant differences in the gene expression among NSCLC subtypes indicate the weakness of DLEC1, TUSC4 and MLH1 expression analysis as potential differentiating markers of NSCLC subtypes in the Polish population.

Pastuszak-Lewandoska D, Kordiak J, Antczak A, et al.
Expression level and methylation status of three tumor suppressor genes, DLEC1, ITGA9 and MLH1, in non-small cell lung cancer.
Med Oncol. 2016; 33(7):75 [PubMed] Related Publications
Despite therapeutic advances, lung cancer remains one of the most common causes of cancer-related death in the world. There is a need to develop biomarkers of diagnostic and/or prognostic value and to translate findings in basic science research to clinical application. Tumor suppressor genes (TSGs) represent potential useful markers for disease detection, progression and treatment target. We tried to elucidate the role of three 3p21.3 TSGs: DLEC1, ITGA9 and MLH1, in non-small cell lung cancer (NSCLC). We assessed their expression pattern by qPCR in 59 NSCLC tissues and in the matched macroscopically unchanged lung tissues. Additionally, we analyzed gene promoter methylation status by methylation-specific PCR in NSCLC samples. We did not find significant correlations between gene expression and methylation. In case of DLEC1 and ITGA9, expression levels were decreased in 71-78 % of tumor samples and significantly different between tumor and normal tissues (P = 0.0001). It could point to their diagnostic value. ITGA9 could also be regarded as a diagnostic marker differentiating NSCLC subtypes, as its expression level was significantly lower in squamous cell carcinoma (P = 0.001). The simultaneous down-regulation of DLEC1 and ITGA9 was observed in 52.5 % of NSCLCs. MSPs revealed high frequencies of gene promoter methylation in NSCLCs: 84 % for DLEC1 and MLH1 and 57 % for ITGA9. Methylation indexes reflected moderate gene methylation levels: 34 % for ITGA9, 27 % for MLH1 and 26 % for DLEC1. However, frequent simultaneous methylation of the studied genes in more than 50 % of NSCLCs suggests the possibility of consider them as a panel of epigenetic markers.

Wang G, Zhang W, Zhou B, et al.
The diagnosis value of promoter methylation of UCHL1 in the serum for progression of gastric cancer.
Biomed Res Int. 2015; 2015:741030 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Aberrant promoter methylation has been considered as a potential molecular marker for gastric cancer (GC). However, the role of methylation of FLNC, THBS1, and UCHL1 in the development and progression of GC has not been explored.
METHODS: The promoter methylation status of UCHL1, FLNC, THBS1, and DLEC1 was assessed by quantitative methylation-specific PCR (QMSP) in the serum of 82 GC patients, 46 chronic atrophic gastritis (CAG) subjects, and 40 healthy controls.
RESULTS: All four genes had significantly higher methylation levels in GC patients than in CAG and control subjects. However, only UCHL1 methylation was significantly correlated with the tumor stage and lymph node metastasis. While THBS1 methylation was altered in an age-dependent manner, FLNC methylation was correlated with differentiation and Helicobacter pylori infection. DLEC1 methylation was only associated with tumor size. Moreover, methylated UCHL1 with or without THBS1 in the serum was found to be significantly associated with a poor prognosis.
CONCLUSION: The promoter methylation degree of FLNC, THBS1, UCHL1, and DLEC1 in serum could tell the existence of GC and only UCHL1 in the serum was also associated with poor prognosis of GC.

Yang Q, Mas A, Diamond MP, Al-Hendy A
The Mechanism and Function of Epigenetics in Uterine Leiomyoma Development.
Reprod Sci. 2016; 23(2):163-75 [PubMed] Free Access to Full Article Related Publications
Uterine leiomyomas, also known as uterine fibroids, are the most common pelvic tumors, occurring in nearly 70% of all reproductive-aged women and are the leading indication for hysterectomy worldwide. The development of uterine leiomyomas involve a complex and heterogeneous constellation of hormones, growth factors, stem cells, genetic, and epigenetic abnormalities. An increasing body of evidence emphasizes the important contribution of epigenetics in the pathogenesis of leiomyomas. Genome-wide methylation analysis demonstrates that a subset of estrogen receptor (ER) response genes exhibit abnormal hypermethylation levels that are inversely correlated with their RNA expression. Several tumor suppressor genes, including Kruppel-like factor 11 (KLF11), deleted in lung and esophageal cancer 1 (DLEC1), keratin 19 (KRT19), and death-associated protein kinase 1 (DAPK1) also display higher hypermethylation levels in leiomyomas when compared to adjacent normal tissues. The important role of active DNA demethylation was recently identified with regard to the ten-eleven translocation protein 1 and ten-eleven translocation protein 3-mediated elevated levels of 5-hydroxymethylcytosine in leiomyoma. In addition, both histone deacetylase and histone methyltransferase are reported to be involved in the biology of leiomyomas. A number of deregulated microRNAs have been identified in leiomyomas, leading to an altered expression of their targets. More recently, the existence of side population (SP) cells with characteristics of tumor-initiating cells have been characterized in leiomyomas. These SP cells exhibit a tumorigenic capacity in immunodeficient mice when exposed to 17β-estradiol and progesterone, giving rise to fibroid-like tissue in vivo. These new findings will likely enhance our understanding of the crucial role epigenetics plays in the pathogenesis of uterine leiomyomas as well as point the way to novel therapeutic options.

Seven D, Yavuz E, Kilic E, et al.
DLEC1 is not silenced solely by promoter methylation in head and neck squamous cell carcinoma.
Gene. 2015; 563(1):83-6 [PubMed] Related Publications
Different types of genetic and epigenetic changes are associated with HNSCC. The molecular mechanisms of HNSCC carcinogenesis are still undergoing intensive investigation. The Deleted in lung and esophageal cancer 1 (DLEC1) gene is frequently silenced by methylation in various kinds of cancer. However, there is no data in the literature investigating the DLEC1 gene in the HNSCC. Tumor tissues from 97 patients were analyzed by real-time quantitative RT-PCR and DLEC1 expression levels were correlated with the methylation of the DLEC1 gene promoter. A statistically significant down-regulation was observed in tumors compared to non-cancerous tissue samples (p = 0.00). However, this down-regulation was not directly associated with hypermethylation of the promoter (p ≥ 0.05). Our results indicate that the DLEC1 gene may play an important role in the development of HNSCC. However, its down-regulation is not associated with the clinicopathological parameters and is not solely under the control of promoter methylation.

Zhang L, Zhang Q, Li L, et al.
DLEC1, a 3p tumor suppressor, represses NF-κB signaling and is methylated in prostate cancer.
J Mol Med (Berl). 2015; 93(6):691-701 [PubMed] Related Publications
UNLABELLED: Deleted in lung and esophageal cancer 1 (DLEC1), located at 3p22-p21.3, is involved in the carcinogenesis of multiple cancers, but its role in prostate cancer (PrCa) remains unclear. Here, we studied the epigenetic alteration of DLEC1 and its functions in prostate cancer. We found that DLEC1 was highly expressed in normal prostate tissues, normal prostatic epithelium cell line (RWPE-1), and benign prostatic hyperplasia cell line (BPH-1), but frequently downregulated by promoter methylation in PrCa cell lines. Pharmacologic demethylation could restore DLEC1 expression. DLEC1 was downregulated in prostate tumor tissues compared with their adjacent non-malignant tissues. DLEC1 was methylated in 76/110 primary tumors, but rarely in benign prostatic hyperplasia tissues. DLEC1 methylation was associated with higher PSA levels (p = 0.016), higher Gleason scores (p = 0.015), and more advanced tumor stages (p = 0.003). Furthermore, DLEC1 methylation was detected in 11/30 urine sediment samples from PrCa patients, but seldom in ones from BPH patients. Ectopic expression of DLEC1 inhibited the colony formation of PrCa cells, through inducing cell apoptosis. DLEC1 also suppressed PrCa cell migration. Moreover, DLEC1 inhibited NF-κB transcription activity in PrCa and HEK293 cells. Taken together, our data demonstrate that DLEC1 functions as a tumor suppressor but is frequently methylated in prostate cancer. DLEC1 methylation is associated with prostate cancer progression, which could be a non-invasive epigenetic biomarker for PrCa diagnosis.
KEY MESSAGES: • Promoter methylation of DLEC1 is a potential prognostic biomarker for PrCa. • DLEC1, a functional tumor suppressor, is frequently methylated in PrCa. • DLEC1 suppresses prostate cancer growth and metastatic behavior. • DLEC1 mediates tumor-suppressive activities through NF-κB signaling.

Guo Y, Shu L, Zhang C, et al.
Curcumin inhibits anchorage-independent growth of HT29 human colon cancer cells by targeting epigenetic restoration of the tumor suppressor gene DLEC1.
Biochem Pharmacol. 2015; 94(2):69-78 [PubMed] Free Access to Full Article Related Publications
Colorectal cancer remains the most prevalent malignancy in humans. The impact of epigenetic alterations on the development of this complex disease is now being recognized. The dynamic and reversible nature of epigenetic modifications makes them a promising target in colorectal cancer chemoprevention and treatment. Curcumin (CUR), the major component in Curcuma longa, has been shown as a potent chemopreventive phytochemical that modulates various signaling pathways. Deleted in lung and esophageal cancer 1 (DLEC1) is a tumor suppressor gene with reduced transcriptional activity and promoter hypermethylation in various cancers, including colorectal cancer. In the present study, we aimed to investigate the inhibitory role of DLEC1 in anchorage-independent growth of the human colorectal adenocarcinoma HT29 cells and epigenetic regulation by CUR. Specifically, we found that CUR treatment inhibited colony formation of HT29 cells, whereas stable knockdown of DLEC1 using lentiviral short hairpin RNA vector increased cell proliferation and colony formation. Knockdown of DLEC1 in HT29 cells attenuated the ability of CUR to inhibit anchorage-independent growth. Methylation-specific polymerase chain reaction (MSP), bisulfite genomic sequencing, and methylated DNA immunoprecipitation revealed that CUR decreased CpG methylation of the DLEC1 promoter in HT29 cells after 5 days of treatment, corresponding to increased mRNA expression of DLEC1. Furthermore, CUR decreased the protein expression of DNA methyltransferases and subtypes of histone deacetylases (HDAC4, 5, 6, and 8). Taken together, our results suggest that the inhibitory effect of CUR on anchorage-independent growth of HT29 cells could, at least in part, involve the epigenetic demethylation and up-regulation of DLEC1.

Ye X, Feng G, Jiao N, et al.
Methylation of DLEC1 promoter is a predictor for recurrence in Chinese patients with gastric cancer.
Dis Markers. 2014; 2014:804023 [PubMed] Free Access to Full Article Related Publications
PURPOSE: To investigate promoter methylation in the deleted in lung and esophageal cancer 1 (DLEC1) gene in Chinese patients with gastric cancer.
METHODS: A total of 227 patients with gastric cancer were enrolled. The methylations of the promoter regions of DLEC1 and ACTB were determined using quantitative methylation-specific PCR. The DLEC1 methylation was compared to the clinicopathological variables of gastric cancer.
RESULTS: DLEC1 methylation was not associated with the clinicopathological variables of gastric cancer. Patients with DLEC1-hypermethylated gastric cancer had significantly higher recurrence rate than those with DLEC1-hypomethylated gastric cancer (P = 0.025; hazard ratio = 2.43).
CONCLUSIONS: Methylation of DELC1 promoter may be a valuable predictor for recurrence in Chinese patients with gastric cancer.

Nawaz I, Qiu X, Wu H, et al.
Development of a multiplex methylation specific PCR suitable for (early) detection of non-small cell lung cancer.
Epigenetics. 2014; 9(8):1138-48 [PubMed] Free Access to Full Article Related Publications
Lung cancer is a worldwide health problem and a leading cause of cancer-related deaths. Silencing of potential tumor suppressor genes (TSGs) by aberrant promoter methylation is an early event in the initiation and development of cancer. Thus, methylated cancer type-specific TSGs in DNA can serve as useful biomarkers for early cancer detection. We have now developed a "Multiplex Methylation Specific PCR" (MMSP) assay for analysis of the methylation status of multiple potential TSGs by a single PCR reaction. This method will be useful for early diagnosis and treatment outcome studies of non-small cell lung cancer (NSCLC). Genome-wide CpG methylation and expression microarrays were performed on lung cancer tissues and matched distant non-cancerous tissues from three NSCLC patients from China. Thirty-eight potential TSGs were selected and analyzed by methylation PCR on bisulfite treated DNA. On the basis of sensitivity and specificity, six marker genes, HOXA9, TBX5, PITX2, CALCA, RASSF1A, and DLEC1, were selected to establish the MMSP assay. This assay was then used to analyze lung cancer tissues and matched distant non-cancerous tissues from 70 patients with NSCLC, as well as 24 patients with benign pulmonary lesion as controls. The sensitivity of the assay was 99% (69/70). HOXA9 and TBX5 were the 2 most sensitive marker genes: 87% (61/70) and 84% (59/70), respectively. RASSF1A and DLEC1 showed the highest specificity at 99% (69/70). Using the criterion of identifying at least any two methylated marker genes, 61/70 cancer samples were positive, corresponding to a sensitivity of 87% and a specificity of 94%. Early stage I or II NSCLC could even be detected with a 100% specificity and 86% sensitivity. In conclusion, MMSP has the potential to be developed into a population-based screening tool and can be useful for early diagnosis of NSCLC. It might also be suitable for monitoring treatment outcome and recurrence.

Ashoor H, Hérault A, Kamoun A, et al.
HMCan: a method for detecting chromatin modifications in cancer samples using ChIP-seq data.
Bioinformatics. 2013; 29(23):2979-86 [PubMed] Free Access to Full Article Related Publications
MOTIVATION: Cancer cells are often characterized by epigenetic changes, which include aberrant histone modifications. In particular, local or regional epigenetic silencing is a common mechanism in cancer for silencing expression of tumor suppressor genes. Though several tools have been created to enable detection of histone marks in ChIP-seq data from normal samples, it is unclear whether these tools can be efficiently applied to ChIP-seq data generated from cancer samples. Indeed, cancer genomes are often characterized by frequent copy number alterations: gains and losses of large regions of chromosomal material. Copy number alterations may create a substantial statistical bias in the evaluation of histone mark signal enrichment and result in underdetection of the signal in the regions of loss and overdetection of the signal in the regions of gain.
RESULTS: We present HMCan (Histone modifications in cancer), a tool specially designed to analyze histone modification ChIP-seq data produced from cancer genomes. HMCan corrects for the GC-content and copy number bias and then applies Hidden Markov Models to detect the signal from the corrected data. On simulated data, HMCan outperformed several commonly used tools developed to analyze histone modification data produced from genomes without copy number alterations. HMCan also showed superior results on a ChIP-seq dataset generated for the repressive histone mark H3K27me3 in a bladder cancer cell line. HMCan predictions matched well with experimental data (qPCR validated regions) and included, for example, the previously detected H3K27me3 mark in the promoter of the DLEC1 gene, missed by other tools we tested.

Tian F, Yip SP, Kwong DL, et al.
Promoter hypermethylation of tumor suppressor genes in serum as potential biomarker for the diagnosis of nasopharyngeal carcinoma.
Cancer Epidemiol. 2013; 37(5):708-13 [PubMed] Related Publications
PURPOSE: Promoter hypermethylation of tumor suppressor genes may serve as a promising biomarker for the diagnosis of cancer. Cell-free circulating DNA (cf-DNA) shares hypermethylation status with primary tumors. This study investigated promoter hypermethylation of five tumor suppressor genes as markers in the detection of nasopharyngeal carcinoma (NPC) in serum samples.
METHODS: cf-DNA was extracted from serum collected from 40 NPC patients and 41 age- and sex-matched healthy subjects. The promoter hypermethylation status of the five genes (RASSF1, CDKN2A, DLEC1, DAPK1 and UCHL1) was assessed by methylation-specific PCR after sodium bisulfite conversion. Differences in the methylation status of these five genes between NPC patients and healthy subjects were compared.
RESULTS: The concentration of cf-DNA in the serum of NPC patients was significantly higher than that in normal controls. The five tumor suppressor genes - RASSF1, CDKN2A, DLEC1, DAPK1 and UCHL1 - were found to be methylated in 17.5%, 22.5%, 25.0%, 51.4% and 64.9% of patients, respectively. The combination of four-gene marker - CDKN2A, DLEC1, DAPK1 and UCHL1 - had the highest sensitivity and specificity in predicting NPC.
CONCLUSION: Screening DNA hypermethylation of tumor suppressor genes in serum was a promising approach for the diagnosis of NPC.

Nikolaev SI, Santoni F, Vannier A, et al.
Exome sequencing identifies putative drivers of progression of transient myeloproliferative disorder to AMKL in infants with Down syndrome.
Blood. 2013; 122(4):554-61 [PubMed] Related Publications
Some neonates with Down syndrome (DS) are diagnosed with self-regressing transient myeloproliferative disorder (TMD), and 20% to 30% of those progress to acute megakaryoblastic leukemia (AMKL). We performed exome sequencing in 7 TMD/AMKL cases and copy-number analysis in these and 10 additional cases. All TMD/AMKL samples contained GATA1 mutations. No exome-sequenced TMD/AMKL sample had other recurrently mutated genes. However, 2 of 5 TMD cases, and all AMKL cases, showed mutations/deletions other than GATA1, in genes proven as transformation drivers in non-DS leukemia (EZH2, APC, FLT3, JAK1, PARK2-PACRG, EXT1, DLEC1, and SMC3). One patient at the TMD stage revealed 2 clonal expansions with different GATA1 mutations, of which 1 clone had an additional driver mutation. Interestingly, it was the other clone that gave rise to AMKL after accumulating mutations in 7 other genes. Data suggest that GATA1 mutations alone are sufficient for clonal expansions, and additional driver mutations at the TMD stage do not necessarily predict AMKL progression. Later in infancy, leukemic progression requires "third-hit driver" mutations/somatic copy-number alterations found in non-DS leukemias. Putative driver mutations affecting WNT (wingless-related integration site), JAK-STAT (Janus kinase/signal transducer and activator of transcription), or MAPK/PI3K (mitogen-activated kinase/phosphatidylinositol-3 kinase) pathways were found in all cases, aberrant activation of which converges on overexpression of MYC.

Rinner B, Weinhaeusel A, Lohberger B, et al.
Chordoma characterization of significant changes of the DNA methylation pattern.
PLoS One. 2013; 8(3):e56609 [PubMed] Free Access to Full Article Related Publications
Chordomas are rare mesenchymal tumors occurring exclusively in the midline from clivus to sacrum. Early tumor detection is extremely important as these tumors are resistant to chemotherapy and irradiation. Despite continuous research efforts surgical excision remains the main treatment option. Because of the often challenging anatomic location early detection is important to enable complete tumor resection and to reduce the high incidence of local recurrences. The aim of this study was to explore whether DNA methylation, a well known epigenetic marker, may play a role in chordoma development and if hypermethylation of specific CpG islands may serve as potential biomarkers correlated with SNP analyses in chordoma. The study was performed on tumor samples from ten chordoma patients. We found significant genomic instability by Affymetrix 6.0. It was interesting to see that all chordomas showed a loss of 3q26.32 (PIK 3CA) and 3q27.3 (BCL6) thus underlining the potential importance of the PI3K pathway in chordoma development. By using the AITCpG360 methylation assay we elucidated 20 genes which were hyper/hypomethylated compared to normal blood. The most promising candidates were nine hyper/hypomethylated genes C3, XIST, TACSTD2, FMR1, HIC1, RARB, DLEC1, KL, and RASSF1. In summary, we have shown that chordomas are characterized by a significant genomic instability and furthermore we demonstrated a characteristic DNA methylation pattern. These findings add new insights into chordoma development, diagnosis and potential new treatment options.

Wang Z, Li L, Su X, et al.
Epigenetic silencing of the 3p22 tumor suppressor DLEC1 by promoter CpG methylation in non-Hodgkin and Hodgkin lymphomas.
J Transl Med. 2012; 10:209 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Inactivaion of tumor suppressor genes (TSGs) by promoter CpG methylation frequently occurs in tumorigenesis, even in the early stages, contributing to the initiation and progression of human cancers. Deleted in lung and esophageal cancer 1 (DLEC1), located at the 3p22-21.3 TSG cluster, has been identified frequently silenced by promoter CpG methylation in multiple carcinomas, however, no study has been performed for lymphomas yet.
METHODS: We examined the expression of DLEC1 by semi-quantitative reverse transcription (RT)-PCR, and evaluated the promoter methylation of DLEC1 by methylation-specific PCR (MSP) and bisulfite genomic sequencing (BGS) in common lymphoma cell lines and tumors.
RESULTS: Here we report that DLEC1 is readily expressed in normal lymphoid tissues including lymph nodes and PBMCs, but reduced or silenced in 70% (16/23) of non-Hodgkin and Hodgkin lymphoma cell lines, including 2/6 diffuse large B-cell (DLBCL), 1/2 peripheral T cell lymphomas, 5/5 Burkitt, 6/7 Hodgkin and 2/3 nasal killer (NK)/T-cell lymphoma cell lines. Promoter CpG methylation was frequently detected in 80% (20/25) of lymphoma cell lines and correlated with DLEC1 downregulation/silencing. Pharmacologic demethylation reversed DLEC1 expression in lymphoma cell lines along with concomitant promoter demethylation. DLEC1 methylation was also frequently detected in 32 out of 58 (55%) different types of lymphoma tissues, but not in normal lymph nodes. Furthermore, DLEC1 was specifically methylated in the sera of 3/13 (23%) Hodgkin lymphoma patients.
CONCLUSIONS: Thus, methylation-mediated silencing of DLEC1 plays an important role in multiple lymphomagenesis, and may serve as a non-invasive tumor marker for lymphoma diagnosis.

Fonseca AL, Kugelberg J, Starker LF, et al.
Comprehensive DNA methylation analysis of benign and malignant adrenocortical tumors.
Genes Chromosomes Cancer. 2012; 51(10):949-60 [PubMed] Related Publications
The molecular pathogenesis of benign and malignant adrenocortical tumors (ACT) is incompletely clarified. The role of DNA methylation in adrenocortical tumorigenesis has not been analyzed in an unbiased, systematic fashion. Using the Infinium HumanMethylation27 BeadChip, the DNA methylation levels of 27,578 CpG sites were investigated in bisulfite-modified DNA from 6 normal adrenocortical tissue samples, 27 adrenocortical adenomas (ACA), and 15 adrenocortical carcinomas (ACC). Genes involved in cell cycle regulation, apoptosis, and transcriptional regulation of known or putative importance in the development of adrenal tumors showed significant and frequent hypermethylation. Such genes included CDKN2A, GATA4, BCL2, DLEC1, HDAC10, PYCARD, and SCGB3A1/HIN1. Comparing benign versus malignant ACT, a total of 212 CpG islands were identified as significantly hypermethylated in ACC. Gene expression studies of selected hypermethylated genes (CDKN2A, GATA4, DLEC1, HDAC10, PYCARD, SCGB3A1/HIN1) in 6 normal and 16 neoplastic adrenocortical tissues (10 ACA and 6 ACC), displayed reduced gene expression in benign and malignant ACT versus normal adrenocortical tissue. Treatment with 5-aza-2'-deoxycytidine of adrenocortical cancer H-295R cells increased expression of the hypermethylated genes CDKN2A, GATA4, DLEC1, HDAC10, PYCARD, and SCGB3A1/HIN1. In conclusion, the current study represents the first unbiased, quantitative, genome-wide study of adrenocortical tumor DNA methylation. Genes with altered DNA methylation patterns were identified of putative importance to benign and malignant adrenocortical tumor development.

Chang PH, Huang CC, Lee TJ, et al.
Downregulation of DLEC1 in sinonasal inverted papilloma and squamous cell carcinoma.
J Otolaryngol Head Neck Surg. 2012; 41(2):94-101 [PubMed] Related Publications
OBJECTIVE: Inverted papilloma is associated with sinonasal squamous cell carcinoma. This study aimed to investigate the epigenetic regulation of the tumour suppressor gene DLEC1 in inverted papilloma and sinonasal squamous cell carcinoma.
METHODS: DLEC1 gene expression was investigated by quantitative real-time polymerase chain reaction (QRT-PCR) in normal mucosa, inverted papilloma, and squamous cell carcinoma tissues. Methylation-specific PCR and subsequent autosequencing were also used to examine the methylation status of DLEC1 promoter and the involved mechanism. DLEC1 expression in a large validation set was evaluated by immunohistochemistry (n  =  25 in each group).
RESULTS: DLEC1 was downregulated in inverted papilloma and squamous cell carcinoma tissues compared to normal mucosa (p < .01 in QRT-PCR and immunohistochemistry), with squamous cell carcinoma more repressed (p < .05 in QRT-PCR and immunohistochemistry) than inverted papilloma tissues. DLEC1 promoter hypermethylation was found in squamous cell carcinoma tissues.
CONCLUSION: Repression of DLEC1 in squamous cell carcinoma tissues is associated with promoter hypermethylation. DLEC1 is downregulated in sinonasal squamous cell carcinoma and inverted papilloma and has a distinct mechanism.

Ricketts CJ, Morris MR, Gentle D, et al.
Genome-wide CpG island methylation analysis implicates novel genes in the pathogenesis of renal cell carcinoma.
Epigenetics. 2012; 7(3):278-90 [PubMed] Free Access to Full Article Related Publications
In order to identify novel candidate tumor suppressor genes (TSGs) implicated in renal cell carcinoma (RCC), we performed genome-wide methylation profiling of RCC using the HumanMethylation27 BeadChips to assess methylation at > 14,000 genes. Two hundred and twenty hypermethylated probes representing 205 loci/genes were identified in genomic CpG islands. A subset of TSGs investigated in detail exhibited frequent tumor methylation, promoter methylation associated transcriptional silencing and reactivation after demethylation in RCC cell lines and down-regulation of expression in tumor tissue (e.g., SLC34A2 specifically methylated in 63% of RCC, OVOL1 in 40%, DLEC1 in 20%, TMPRSS2 in 26%, SST in 31% and BMP4 in 35%). As OVOL1, a putative regulator of c-Myc transcription, and SST (somatostatin) had not previously been linked to cancer and RCC, respectively, we (1) investigated their potential relevance to tumor growth by RNAi knockdown and found significantly increased anchorage-independent growth and (2) demonstrated that OVOL1 knockdown increased c-Myc mRNA levels.

Navarro A, Yin P, Monsivais D, et al.
Genome-wide DNA methylation indicates silencing of tumor suppressor genes in uterine leiomyoma.
PLoS One. 2012; 7(3):e33284 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Uterine leiomyomas, or fibroids, represent the most common benign tumor of the female reproductive tract. Fibroids become symptomatic in 30% of all women and up to 70% of African American women of reproductive age. Epigenetic dysregulation of individual genes has been demonstrated in leiomyoma cells; however, the in vivo genome-wide distribution of such epigenetic abnormalities remains unknown.
PRINCIPAL FINDINGS: We characterized and compared genome-wide DNA methylation and mRNA expression profiles in uterine leiomyoma and matched adjacent normal myometrial tissues from 18 African American women. We found 55 genes with differential promoter methylation and concominant differences in mRNA expression in uterine leiomyoma versus normal myometrium. Eighty percent of the identified genes showed an inverse relationship between DNA methylation status and mRNA expression in uterine leiomyoma tissues, and the majority of genes (62%) displayed hypermethylation associated with gene silencing. We selected three genes, the known tumor suppressors KLF11, DLEC1, and KRT19 and verified promoter hypermethylation, mRNA repression and protein expression using bisulfite sequencing, real-time PCR and western blot. Incubation of primary leiomyoma smooth muscle cells with a DNA methyltransferase inhibitor restored KLF11, DLEC1 and KRT19 mRNA levels.
CONCLUSIONS: These results suggest a possible functional role of promoter DNA methylation-mediated gene silencing in the pathogenesis of uterine leiomyoma in African American women.

Montavon C, Gloss BS, Warton K, et al.
Prognostic and diagnostic significance of DNA methylation patterns in high grade serous ovarian cancer.
Gynecol Oncol. 2012; 124(3):582-8 [PubMed] Related Publications
OBJECTIVE: Altered DNA methylation patterns hold promise as cancer biomarkers. In this study we selected a panel of genes which are commonly methylated in a variety of cancers to evaluate their potential application as biomarkers for prognosis and diagnosis in high grade serous ovarian carcinoma (HGSOC); the most common and lethal subtype of ovarian cancer.
METHODS: The methylation patterns of 10 genes (BRCA1, EN1, DLEC1, HOXA9, RASSF1A, GATA4, GATA5, HSULF1, CDH1, SFN) were examined and compared in a cohort of 80 primary HGSOC and 12 benign ovarian surface epithelium (OSE) samples using methylation-specific headloop suppression PCR.
RESULTS: The genes were variably methylated in primary HGSOC, with HOXA9 methylation observed in 95% of cases. Most genes were rarely methylated in benign OSE, with the exception of SFN which was methylated in all HGSOC and benign OSE samples examined. Methylation of DLEC1 was associated with disease recurrence, independent of tumor stage and suboptimal surgical debulking (HR 3.5 (95% CI:1.10-11.07), p=0.033). A combination of the methylation status of HOXA9 and EN1 could discriminate HGSOC from benign OSE with a sensitivity of 98.8% and a specificity of 91.7%, which increased to 100% sensitivity with no loss of specificity when pre-operative CA125 levels were also incorporated.
CONCLUSIONS: This study provides further evidence to support the feasibility of detecting altered DNA methylation patterns as a potential diagnostic and prognostic approach for HGSOC.

Park SY, Kwon HJ, Choi Y, et al.
Distinct patterns of promoter CpG island methylation of breast cancer subtypes are associated with stem cell phenotypes.
Mod Pathol. 2012; 25(2):185-96 [PubMed] Related Publications
Although DNA methylation profiles in breast cancer have been connected to breast cancer molecular subtype, there have been no studies of the association of DNA methylation with stem cell phenotype. This study was designed to evaluate the promoter CpG island methylation of 15 genes in relation to breast cancer subtype, and to investigate whether the patterns of CpG island methylation in each subtype are associated with their cancer stem cell phenotype represented by CD44+/CD24- and ALDH1 expression. We performed MethyLight analysis of the methylation status of 15 promoter CpG island loci involved in breast cancer progression (APC, DLEC1, GRIN2B, GSTP1, HOXA1, HOXA10, IGF2, MT1G, RARB, RASSF1A, RUNX3, SCGB3A1, SFRP1, SFRP4, and TMEFF2) and determined cancer stem cell phenotype by CD44/CD24 and ALDH1 immunohistochemistry in 36 luminal A, 33 luminal B, 30 luminal-HER2, 40 HER2 enriched, and 40 basal-like subtypes of breast cancer. The number of CpG island loci methylated differed significantly between subtypes, and was highest in the luminal-HER2 subtype and lowest in the basal-like subtype. Methylation frequencies and levels in 12 of the 15 genes differed significantly between subtypes, and the basal-like subtype had significantly lower methylation frequencies and levels in nine of the genes than the other subtypes. CD44+/CD24- and ALDH1+ putative stem cell populations were most enriched in the basal-like subtype. Methylation of promoter CpG islands was significantly lower in CD44+/CD24-cell (+) tumors than in CD44+/CD24-cell (-) tumors, even within the basal-like subtype. ALDH1 (+) tumors were also less methylated than ALDH1 (-) tumors. Our findings showed that promoter CpG island methylation was different in relation to breast cancer subtype and stem cell phenotype of tumor, suggesting that breast cancers have distinct patterns of CpG island methylation according to molecular subtypes and these are associated with different stem cell phenotypes of the tumor.

Wang Z, Yuan X, Jiao N, et al.
CDH13 and FLBN3 gene methylation are associated with poor prognosis in colorectal cancer.
Pathol Oncol Res. 2012; 18(2):263-70 [PubMed] Related Publications
The aim of this study was to identify potential epigenetic prognostic biomarkers for colorectal cancer (CRC) in the Chinese population. The methylation status of five tumor suppressor genes (CDH13, DLEC1, FBLN3, hMHL1 and RUNX3) was determined using manual microdissection followed by methylation-specific PCR in 85 paired CRC specimens and adjacent normal tissue. The results showed that methylation frequencies in cancerous tissues were 31.8% for CDH13, 37.6% for DLEC1, 38.8% for FBLN3, 22.4% for hMHL1 and 27.1% for RUNX3, all of which were significantly higher than in corresponding normal tissue. Furthermore, CDH13 methylation was associated with poor differentiation (P = 0.019) and tended to be predominant in advanced stages (P = 0.084); FBLN3 methylation was associated with advanced stages (P = 0.027) and lymph node metastasis (P = 0.029). Accordingly, the methylation status of CDH13 (P = 0.022), FBLN3 (P = 0.008), CDH13 and/or FBLN3 (P = 0.001) predicted adverse overall survival in CRC, while hMHL1 methylation showed a protective role in survival (P = 0.046). Cox proportional hazard models further indicated that CDH13 and/or FBLN3 methylation, but not that of hMHL1, was an independent prognostic factor for CRC. In conclusion, we found CDH13 and FBLN3 gene methylation are potential biomarkers for poor prognosis in CRC.

Chung JH, Lee HJ, Kim BH, et al.
DNA methylation profile during multistage progression of pulmonary adenocarcinomas.
Virchows Arch. 2011; 459(2):201-11 [PubMed] Related Publications
Multiple genetic and epigenetic alterations are known to be involved in the carcinogenesis of peripheral pulmonary adenocarcinoma (ADC). However, epigenetic abnormalities have not been extensively investigated in the following multistage progression sequence: atypical adenomatous hyperplasia (AAH) to adenocarcinoma in situ (AIS), to invasive ADC. To determine the potential role of promoter methylation during ADC development of the lung, we examined methylation status in 20 normal, 20 AAH, 30 AIS, and 60 ADC lung tissues and compared methylation status among the lesions. The MethyLight assay was used to determine the methylation status of 18 CpG island loci, which were hypermethylated in ADC compared to noncancerous lung tissues. The mean number of methylated CpG island loci was significantly higher in ADC than in AAH and AIS, (p < 0.003 between ADC and AAH, p < 0.005 between ADC and AIS). Aberrant methylation of HOXA1, TMEFF2, and RARB was frequently observed in preinvasive lesions, including AAH and AIS. Furthermore, methylation of PENK, BCL2, RUNX3, DLEC1, MT1G, GRIN2B, CDH13, CCND2, and HOXA10 was significantly more frequent in invasive ADC than AAH or AIS. Our results indicate that epigenetic alterations are involved in the multistep progression of pulmonary ADC development, and aberrant CpG island methylation accumulates during multistep carcinogenesis. In addition, aberrant methylation of HOXA1, TMEFF2, and RARB occurred in preinvasive lesions, which indicates that epigenetic alterations of these genes are involved in the early stages of pulmonary ADC development. In contrast, hypermethylation of PENK, BCL2, RUNX3, DLEC1, MT1G, GRIN2B, CDH13, CCND2, and HOXA10 was more frequent in invasive ADC than in preinvasive lesions, which indicates that methylation of these genes occurs later during tumor invasion in the AAH-AIS-ADC sequence.

Zhang Y, Ye X, Geng J, Chen L
Epigenetic inactivation of deleted in lung and esophageal cancer 1 gene by promoter methylation in gastric and colorectal adenocarcinoma.
Hepatogastroenterology. 2010 Nov-Dec; 57(104):1614-9 [PubMed] Related Publications
BACKGROUND/AIM: Deleted in Lung and Esophageal Cancer 1 (DLEC1) gene was a new candidate tumor suppressor gene, we evaluated the diagnostic role of DLEC1 methylation in gastric adenocarcinoma (GAC) and colorectal adenocarcinoma (CRAC).
METHODOLOGY: Methylation-specific polymerase chain reaction (MSP) was used to determine the promoter methylation status of DLEC1 gene in tissue and serum DNA. DLEC1 gene expression was determined by immunohistochemistry.
RESULTS: DLEC1 methylation was detected in 38.5% (25/65) of GAC and 45.1% (32/71) of CRAC tissues, while seldom in the adjacent normal tissues of stomach (8.0%, 4/50) and colorectum (7.1%, 4/56) (p < 0.001). The hypermethylation status of DLEC1 was associated with low or absent of DLEC1 protein expression both in tumor and pre-malignant lesions (p < 0.001), but not correlated with patients' clinicopathological features and elevated CEA/CA19-9 levels. Moreover, 33.8% (22/65) of GAC and 39.4% (28/71) of CRAC serums had DLEC1 methylation, which was higher than that in the serums of cancer-free controls (p < 0.001), and the concordance of DLEC1 methylation in tumor tissues and corresponding serum samples was well.
CONCLUSION: Epigenetic inactivation of DLEC1 was crucial in gastric and colorectal carcinogenesis. DLEC1 methylation in serum may be a promise biomarker for GAC and CRAC early diagnosis.

Song H, Yi J, Zhang Y, et al.
[DNA methylation of tumor suppressor genes located on chromosome 3p in non-small cell lung cancer].
Zhongguo Fei Ai Za Zhi. 2011; 14(3):233-8 [PubMed] Free Access to Full Article Related Publications
BACKGROUND AND OBJECTIVE: DNA methylation is one of the mechanisms of epigenetics. Allelic loss located on chromosome 3p happen frequently and early in non-small cell lung cancer (NSCLC). The aim of this study is to detect the promoter methylation status of tumor suppressor genes (TSGs) located on chromosome 3p in NSCLC and to evaluate its correlation with clinicopathological features.
METHODS: A total of 78 paired NSCLC specimens and their adjacent normal tissues were collected in the study. Promoter methylation status was determined by methylation-specific polymerase chain reaction (MSP). DLEC1 gene expression was determined by RT-PCR and immunohistochemistry.
RESULTS: Aberrant methylation frequency of DLEC1, RASSF1A, hMLH1, RARβ and FHIT genes detected in 78 NSCLC tissues were 41.03%, 39.74%, 30.77% and 16.67%, respectively, which were all significantly higher than that in adjacent normal tissues. However, FHIT gene was not detected methylation in both cancerous and non-cancerous tissues. DLEC1 hypermethylation was associated with advanced stage (P=0.011) and lymph metastasis (P=0.019), while RASSF1A, RARβ, hMLH1 and mean methylation index (MI) were not correlated with any clinicopathological parameters. Moreover, DLEC1 gene downregulation was detected in 56.41% (44/78) NSCLC tissues and correlated with promoter hypermethylation.
CONCLUSIONS: Frequent hypermethylation of TSGs located on chromosome 3p was a common event contributing to NSCLC pathogenesis and DLEC1 methylation was closely correlated with loss of expression.

Daigo Y, Nishiwaki T, Kawasoe T, et al.
Molecular cloning of a candidate tumor suppressor gene, DLC1, from chromosome 3p21.3.
Cancer Res. 1999; 59(8):1966-72 [PubMed] Related Publications
The short arm of chromosome 3 is thought to contain multiple tumor suppressor genes, because one copy of this chromosomal arm frequently is missing in carcinomas that have arisen in a variety of tissues. We have isolated a novel gene encoding a 1755-amino acid polypeptide, through large-scale sequencing of genomic DNA at 3p21.3. Mutational analysis of this gene by reverse transcription-PCR revealed the lack of functional transcripts and an increase of nonfunctional RNA transcripts in a significant proportion (33%) of cancer cell lines and primary cancers (4 of 14 esophageal cancer cell lines, 2 of 2 renal cancer cell lines, 11 of 30 primary non-small cell lung cancers, and 3 of 10 primary squamous cell carcinomas of the esophagus). However, no alterations of the gene itself were detected in any of the cancers examined. Introduction of the cDNA significantly suppressed the growth of four different cancer cell lines, two of which produced no normal transcript on their own. No such effect occurred when antisense cDNA, cDNA corresponding to an aberrant transcript, or the vector DNA alone were transfected. These data suggest that aberrant transcription of this gene, designated DLC1 (deleted in lung cancer 1), may be involved in carcinogenesis of the lung, esophagus, and kidney.

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