DNA methylation profile in diffuse type gastric cancer: evidence for hypermethylation of the BRCA 1 promoter region in early-onset gastric carcinogenesis
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Date
2008
Journal Title
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Volume Title
Publisher
SOC BIOLGIA CHILE
Abstract
Diffuse type gastric carcinoma is the most aggressive type of gastric cancer. This type Of tumor is not preceded by precancerous changes and is associated with carly-onset and hereditary syndromes. To test the hypothesis that DNA methylation profile Would be useful for molecular classification of the diffuse type gastric carcinoma, DNA methylation patterns of the CpG Island of 17 genes were studied in 104 cases and 47 normal adjacent gastric mucosa by Methylation-specific PCR, Immunohistochemistry and Hierarchical Clustering analysis. The most frequent methylated genes were FHIT, E-cadherin, BRCA1 and APC (>50%), followed by p14, p16, p15, p73, MGMT and SEMA3B (20-49%). Hierarchical clustering analysis reveals four groups with different clinical features. The first was characterized by hypermethylation of BRCA 1 and younger age (<45 years old), and the second by hypermethylation of p14 and p 16 genes, male. predominance and Epstein-Barr virus infection. The third group was characterized by hypermethylation of FHIT and antrum located tumors and the fourth was not associated with any clinical variables. In normal adjacent mucosa only the p73 gene was significantly less methylated in comparison to tumor mucosa. DNA methylation identified subgroups of diffuse type gastric cancer. Hypermethylation of BRCA I associated with Young age suggests a role in early-onset gastric carcinoma.
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Keywords
gastric cancer, diffuse type, early-onset, BRCA-1, CPG ISLAND METHYLATION, EPSTEIN-BARR-VIRUS, TUMOR-SUPPRESSOR GENES, SIGNET-RING CELL, GALLBLADDER CARCINOMA, ABERRANT METHYLATION, MULTIPLE GENES, OVARIAN-CANCER, EXPRESSION, PROGRESSION