title: Quantitative promoter hypermethylation analysis of RASSF1A in lung cancer: comparison with methylation-specific PCR technique and clinical significance.
abstract: Lung cancer is the major health problem and leading cause of cancer-related deaths worldwide owing to late diagnosis and poor prognosis. Aberrant promoter methylation is an important mechanism for silencing tumor-suppressor genes in cancer and a promising tool for the development of molecular biomarkers. Ras association domain family 1A (RASSF1A), a pivotal gatekeeper of cell cycle progression, is highly methylated in a wide range of human sporadic tumors, including lung cancer. However, no significant prognostic implications have been observed in most studies qualitatively analyzed by methylation-specific PCR (MSP). We found that the RASSF1A promoter was aberrantly methylated in 44.7 and 37.4% of the tumors by pyrosequencing (PS) and MSP methods, respectively. RASSF1A methylation evaluated by the two methods was more frequent in ever-smokers and tumors with TP53 mutation than in never-smokers and tumors without TP53 mutation, respectively. Univariate and multivariate analyses revealed that strong methylation was an unfavorable prognostic factor with stage I (adjusted HR, 2.25; 95% CI 1.03-4.90; P=0.003) and squamous cell carcinoma patients (adjusted HR=2.25, 95% CI 1.03-4.90, P=0.042). Taken together, these results suggested that quantitative PS could gain wider applications in clinical samples as a promising method for early detection screening and prognosis compared with MSP.
authors.affiliation: Department of Anatomy, School of Medicine, Kyungpook National                     University, Daegu 702-422, Republic of Korea.
authors.forename: Su Man
authors.initials: SM
authors.lastname: Lee
authors.forename: Won Kee
authors.initials: WK
authors.lastname: Lee
authors.forename: Dong Sun
authors.initials: DS
authors.lastname: Kim
authors.forename: Jae Yong
authors.initials: JY
authors.lastname: Park
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D019175:DNA Methylation; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D012907:Smoking; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C411762:RASSF1 protein, human; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins