ABERRANT DNA METHYLATION AS A CANCER-INDUCING MECHANISM

2005 ◽  
Vol 45 (1) ◽  
pp. 629-656 ◽  
Author(s):  
Manel Esteller
Keyword(s):  
Dna Methylation ◽  
Tumor Suppressor ◽  
Tumor Suppressor Genes ◽  
Cpg Island ◽  
Gene Mutations ◽  
Promoter Hypermethylation ◽  
Dna Methyltransferases ◽  
Tumor Type ◽  
Suppressor Genes ◽  
Aberrant Dna Methylation

Aberrant DNA methylation is the most common molecular lesion of the cancer cell. Neither gene mutations (nucleotide changes, deletions, recombinations) nor cytogenetic abnormalities are as common in human tumors as DNA methylation alterations. The most studied change of DNA methylation in neoplasms is the silencing of tumor suppressor genes by CpG island promoter hypermethylation, which targets genes such as p16INK4a, BRCA1, and hMLH1. There is a profile of CpG island hypermethylation according to the tumor type, and genes silent by methylation represent all cellular pathways. The introduction of bisulfite-PCR methodologies combined with new genomic approaches provides a comprehensive spectrum of the genes undergoing this epigenetic change across all malignancies. However, we still know very little about how this aberrant DNA methylation “invades” the previously unmethylated CpG island and how it is maintained through cell divisions. Furthermore, we should remember that this methylation occurs in the context of a global genomic loss of 5-methylcytosine (5mC). Initial clues to understand this paradox should be revealed from the current studies of DNA methyltransferases and methyl CpG binding proteins. From the translational standpoint, we should make an effort to validate the use of some hypermethylated genes as biomarkers of the disease; for example, it may occur with MGMT and GSTP1 in brain and prostate tumors, respectively. Finally, we must expect the development of new and more specific DNA demethylating agents that awake these methyl-dormant tumor suppressor genes and prove their therapeutic values. The expectations are high.

Aberrant DNA methylation of some tumor suppressor genes in lung cancers from workers with chromate exposure

2010 ◽  
Vol 50 (2) ◽  
pp. 89-99 ◽  
Author(s):  
Abdellah H. K. Ali ◽  
Kazuya Kondo ◽  
Toshiaki Namura ◽  
Yoshitaka Senba ◽  
Hiromitsu Takizawa ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Tumor Suppressor ◽  
Tumor Suppressor Genes ◽  
Suppressor Genes ◽  
Lung Cancers ◽  
Aberrant Dna Methylation ◽  
Chromate Exposure

Promoter Methylation of Multiple Genes in Germinal Center Hyperplasia and Lymphomas of Germinal Center Origin

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4487-4487
Author(s):  
Jose M Paz-Carreira ◽  
Raquel Losada ◽  
Arantxa Garcia-Rivero ◽  
Augusto Alvarez ◽  
Fernando Bal ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Tumor Suppressor ◽  
B Cell ◽  
Promoter Methylation ◽  
Germinal Center ◽  
Tumor Suppressor Genes ◽  
Methylation Status ◽  
Promoter Hypermethylation ◽  
Epigenetic Mechanism ◽  
Suppressor Genes

Abstract INTRODUCTION. Germinal centers (GC) are unique sites in peripheral lymphoid tissue where clonal selection of B cells takes place. This occurs as a response to stimulation by various antigens originating, sometimes, follicular hyperplasia (FH). GC have been known as a major source of B-cell lymphomas including follicular (FL) and diffuse large cell (DLCL). DNA methylation of tumor-suppressor genes is a mechanism of gene silencing involved in the pathogenesis of FL and DLCL. Much less is known about the role of methylation in FH. We determined the methylation status of 6 tumor-suppressor genes in 43 patients with FH, 18 patients with FL and 49 patients with DLCL in order to see the differential implication of this epigenetic mechanism in the pathological and the physiological development of GC. MATERIAL AND METHODS. Genomic DNA extracted from paraffin-embedded samples of 43 FH, 18 FL and 49 DLCL after being treated with EZ DNA-Methylation Kit (Zymo Research) with the manufacturer’s instructions, were analyzed by methylation-specific polymerase chain-reaction to determine promoter hypermethylation of DAP-k, SHP1, Rarβ, p14, SHP1, MGMT and PDRM1. All samples were obtained mostly from lymph nodes and tonsils. Diagnosis was based on morphology and immunohistochemistry analysis. All cases were matched for age, sex and ethnic origin. RESULTS: DAP-k promoter methylation occurred with higher frequency in FL(89%) than in DLCL(78%) and FH(40%). SHP1 was methylated in 61% of FL, 58% of FH and 23% of DLCL. RARb was methylated in 67% of FL patients, 30% of DLCL and only 12% of FH. Eight (44%) FL, seventeen (35%) DLCL and four (10%) BFH patients showed MGMT methylation. Promoter hypermethylation of p14 was detected only in 5 (12%) FH, 2 (4%) DLCL and none FL patients. Methylation of PRMD1 was present only in 1 (6%) FL, 2 (6%) DLCL and 1 (4%) FH samples. CONCLUSIONS. Inactivacion of DAP-K and SHP1 is present in B-cell malignancies, DLCL and FL, and BFH. Therefore, it may represent a physiologic event conferring a temporal survival advantage necessary for a GC hyperplastic response. Inactivation of the retinoic acid response through the methylation of Rarâ is significantly more frequent in lymphomas than in FH. As reported in other tumors methylation of MGMT is more frequent in lymphomas than in FH. With our data methylation of Cyclin dependent kinase inhibitors p14 is not a differential pathogenic event in lymphomas of GC origin, in fact it is more frequent in FH. Promoter Methylation of PDRM1 is not the mechanism involved in lymphomagenesis in FL and DLCL, the two FH positive deserve further follow-up to determine its significance.

scholarly journals Aberrant DNA Methylation in Cholangiocarcinoma

2017 ◽  
Author(s):  
Toshiaki Nakaoka ◽  
Yoshimasa Saito ◽  
Hidetsugu Saito
Keyword(s):  
Dna Methylation ◽  
Immune Response ◽  
Tumor Suppressor ◽  
Tumor Suppressor Genes ◽  
Ampulla Of Vater ◽  
Endogenous Retroviruses ◽  
Epigenetic Therapy ◽  
Suppressor Genes ◽  
Aberrant Dna Methylation ◽  
Dna Methylation Inhibitors

Cholangiocarcinoma is an epithelial malignancy arising in the region between the intrahepatic bile ducts and the ampulla of Vater at the distal end of the common bile duct. The effect of current chemotherapy regimens against cholangiocarcinoma is limited, and the prognosis of patients with cholangiocarcinoma is poor. Aberrant DNA methylation and histone modification induce silencing of tumor suppressor genes and chromosomal instability during carcinogenesis. Studies have shown that the tumor suppressor genes and microRNAs (miRNAs) including MLH1, p14, p16, DAPK, miR-370 and miR-376c are frequently methylated in cholangiocarcinoma. Silencing of these tumor suppressor genes and miRNAs plays critical roles in the initiation and progression of cholangiocarcinoma. In addition, recent studies have demonstrated that DNA methylation inhibitors induce expression of endogenous retroviruses and exert the anti-tumor effect of via an anti-viral immune response. Aberrant DNA methylation of tumor suppressor genes and miRNAs could be a powerful biomarker for diagnosis and treatment of cholangiocarcinoma. Epigenetic therapy with DNA methylation inhibitors hold considerable promise for the treatment of cholangiocarcinoma through re-activation of tumor suppressor genes and miRNAs as well as induction of an anti-viral immune response.

Development of a novel approach, the epigenome-based outlier approach, to identify tumor-suppressor genes silenced by aberrant DNA methylation

2012 ◽  
Vol 322 (2) ◽  
pp. 204-212 ◽  
Author(s):  
Mizuho Kikuyama ◽  
Hideyuki Takeshima ◽  
Takayuki Kinoshita ◽  
Eriko Okochi-Takada ◽  
Mika Wakabayashi ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Tumor Suppressor ◽  
Tumor Suppressor Genes ◽  
Suppressor Genes ◽  
Novel Approach ◽  
Aberrant Dna Methylation

scholarly journals DNA methylation profiling in MEN1-related pancreatic neuroendocrine tumors reveals a potential epigenetic target for treatment

2018 ◽  
Vol 179 (3) ◽  
pp. 153-160 ◽  
Author(s):  
E B Conemans ◽  
L Lodewijk ◽  
C B Moelans ◽  
G J A Offerhaus ◽  
C R C Pieterman ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Tumor Suppressor ◽  
Promoter Methylation ◽  
Tumor Suppressor Genes ◽  
Gene Promoter ◽  
Pancreatic Neuroendocrine Tumor ◽  
Promoter Hypermethylation ◽  
Suppressor Gene ◽  
Suppressor Genes ◽  
Frequent Event

ObjectiveEpigenetic changes contribute to pancreatic neuroendocrine tumor (PanNET) development. Hypermethylation of promoter DNA as a cause of tumor suppressor gene silencing is a well-established oncogenic mechanism that is potentially reversible and therefore an interesting therapeutic target. Multiple endocrine neoplasia type 1 (MEN1) is the most frequent cause of inherited PanNETs. The aim of this study was to determine promoter methylation profiles in MEN1-related PanNETs.Design and methodsMethylation-specific multiplex ligation-dependent probe amplification was used to assess promoter methylation of 56 tumor suppressor genes in MEN1-related (n = 61) and sporadic (n = 34) PanNETs. Differences in cumulative methylation index (CMI), individual methylation percentages and frequency of promoter hypermethylation between subgroups were analyzed.ResultsWe found promoter methylation of a large number of potential tumor suppressor genes. CMI (median CMI: 912 vs 876,P = 0.207) was the same in MEN1-related and sporadic PanNETs. We found higher methylation percentages ofCASP8in MEN1-related PanNETs (median: 59% vs 16.5%,P = 0.002). In MEN1-related non-functioning PanNETs, the CMI was higher in larger PanNETs (>2 cm) (median: 969.5 vs 838.5;P = 0.021) and in PanNETs with liver metastases (median: 1036 vs 869;P = 0.013). Hypermethylation ofMGMT2was more frequent in non-functioning PanNETs compared to insulinomas (median: 44.7% vs 8.3%;P = 0.022). Hypermethylation of the Von Hippel–Lindau gene promoter was observed in one MEN1-related PanNET and was associated with loss of protein expression.ConclusionPromoter hypermethylation is a frequent event in MEN1-related and sporadic PanNETs. Targeting DNA methylation could be of therapeutic value in MEN1 patients with advanced PanNETs.

scholarly journals Consistent DNA Hypermethylation Patterns in Laryngeal Papillomas

2010 ◽  
Vol 1 (2) ◽  
pp. 69-77 ◽  
Author(s):  
Josena K Stephen ◽  
Kang Mei Chen ◽  
Veena Shah ◽  
Vanessa G Schweitzer ◽  
Glendon Gardner ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Tumor Suppressor ◽  
Tumor Suppressor Genes ◽  
Methylation Status ◽  
Promoter Hypermethylation ◽  
Aberrant Methylation ◽  
Dna Hypermethylation ◽  
Suppressor Genes ◽  
Multiple Tumor ◽  
Specific Pcr

Abstract Introduction This study examined the contribution of promoter hypermethylation to the pathogenesis of respiratory papillomatosis (RP), including recurrences (RRP) and progression to squamous cell carcinoma (SSC). Materials and methods A retrospective cohort of 25 laryngeal papilloma cases included 21 RRP, two of which progressed to SCC. Aberrant methylation status was determined using the multigene (22 tumor suppressor genes) methylation-specific multiplex ligationdependent probe amplification assay and confirmed using methylation specific PCR. Results Twenty genes had altered DNA methylation in 22 of 25 cases. Aberrant methylation of CDKN2B and TIMP3 was most frequent. Promoter hypermethylation of BRCA2, APC, CDKN2A and CDKN2B was detected in 2 RRP cases with subsequent progression to SCC. Of the 25 cases, 22 were positive for HPV-6, 2 for HPV-11 and 1 for HPV-16 and 33. Conclusion Consistent aberrant methylation of multiple tumor suppressor genes contributes to the pathogenesis of laryngeal papillomas. Persistent aberrant DNA methylation events in 2 RRP cases that progressed to cancer indicate an epigenetic monoclonal progression continuum to SCC.

scholarly journals Promoter Hypermethylation of Tumor-Suppressor Genes p16INK4a, RASSF1A, TIMP3, and PCQAP/MED15 in Salivary DNA as a Quadruple Biomarker Panel for Early Detection of Oral and Oropharyngeal Cancers

Biomolecules ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 148 ◽  
Author(s):  
Chamikara Liyanage ◽  
Asanga Wathupola ◽  
Sanjayan Muraleetharan ◽  
Kanthi Perera ◽  
Chamindie Punyadeera ◽  
...  
Keyword(s):  
Risk Factors ◽  
Dna Methylation ◽  
Tumor Suppressor ◽  
Early Detection ◽  
Tumor Suppressor Genes ◽  
Promoter Hypermethylation ◽  
Healthy Controls ◽  
Suppressor Genes ◽  
Marker Panel ◽  
Methylation Marker

Silencing of tumor-suppressor genes (TSGs) by DNA promoter hypermethylation is an early event in carcinogenesis; hence, TSGs may serve as early tumor biomarkers. We determined the promoter methylation levels of p16INK4a, RASSF1A, TIMP3, and PCQAP/MED15 TSGs in salivary DNA from oral cancer (OC) and oropharyngeal cancer (OPC) patients, using methylation-specific PCR coupled with densitometry analysis. We assessed the association between DNA methylation of individual TSGs with OC and OPC risk factors. The performance and the clinical validity of this quadruple-methylation marker panel were evaluated in discriminating OC and OPC patients from healthy controls using the CombiROC web tool. Our study reports that RASSF1A, TIMP3, and PCQAP/MED15 TSGs were significantly hypermethylated in OC and OPC cases compared to healthy controls. DNA methylation levels of TSGs were significantly augmented by smoking, alcohol use, and betel quid chewing, indicating the fact that frequent exposure to risk factors may drive oral and oropharyngeal carcinogenesis through TSG promoter hypermethylation. Also, this quadruple-methylation marker panel of p16INK4a, RASSF1A, TIMP3, and PCQAP/MED15 TSGs demonstrated excellent diagnostic accuracy in the early detection of OC at 91.7% sensitivity and 92.3% specificity and of OPC at 99.8% sensitivity and 92.1% specificity from healthy controls.

Association Between Cyclin D1 Polymorphism with CpG Island Promoter Methylation Status of Tumor Suppressor Genes in Gastric Cancer

2010 ◽  
Vol 55 (12) ◽  
pp. 3449-3457 ◽  
Author(s):  
Tomomitsu Tahara ◽  
Tomoyuki Shibata ◽  
Masakatsu Nakamura ◽  
Hiromi Yamashita ◽  
Daisuke Yoshioka ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Tumor Suppressor ◽  
Cyclin D1 ◽  
Promoter Methylation ◽  
Tumor Suppressor Genes ◽  
Cpg Island ◽  
Methylation Status ◽  
Suppressor Genes ◽  
Promoter Methylation Status
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