title: RASSF1A, APC, ESR1, ABCB1 and HOXC9, but not p16INK4A, DAPK1, PTEN and MT1G genes were frequently methylated in the stage I non-small cell lung cancer in China.
abstract: OBJECTIVE
  To identify the DNA methylation biomarkers for the detection of the stage I non-small cell lung cancer (NSCLC).
  
  
  METHODS
  The methylated state of p16INK4A, ESR1, HOX9, RASSF1A, DAPK1, PTEN, ABCB1, MGMT, APC and MT1G genes that have been reported frequently methylated in lung cancer was determined using methylation-specific PCR in four lung cancer cell lines, 124 cancer tissues of the stage I NSCLC and 26 non-cancerous disease tissues.
  
  
  RESULTS
  The RASSF1A (53/124, 42.74%), APC (49/123, 39.52%), ESR1 (37/124, 29.84%), ABCB1 (31/124, 24.19%, MT1G (25/124, 20.16%) and HOXC9 (17/124, 13.71%) genes were more frequently methylated in the lung tissue from the stage I NSCLC than the non-cancerous lesion patients (2/26, 7.69%, P < 0.01; 2/26, 7.69%, P < 0.01; 2/26, 7.69%, P < 0.05; 1/26, 3.85% P < 0.01; 0/26 0%, P value: <0.01; 0/26, 0%, P < 0.05, respectively). p16INK4A was methylated in 28/124 (22.56%) of cancer tissues and 2/26 (7.69%) of non-cancerous tissues (P value >0.05). No significant association between the methylated state of the genes and the smoking, age or the pathologic types (squamous carcinoma, adenoma and the mixed types) was found. However, p16INK4A methylation was more frequently detected in the male (23/80, 28.75%) than the female (5/44, 11.36%, P > 0.05) patients. MGMT was barely methylated: 1/67, 1.49%), while DAPK1 and PTEN were not at all methylated in the cancer groups.
  
  
  CONCLUSIONS
  Methylation analysis in tissue of RASSF1A, APC, ESR1, ABCB1 and HOXC9 genes confirmed 79.8% of the existing diagnosis for the stage I NSCLC at specificity: 73.1%. The insufficiency of predicting disease onset in China, using the previously recommended targets (MGMT, DAPK1 and PTEN) in the United States reflects a potential disease disparity between these two populations. Alternatively, methylated state of this set of genes may be more specific to the late rather than the early stage of NSCLC.
authors.affiliation: The First Hospital Affiliated to Suzhou University,215006 Suzhou, Jiangsu, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Lin
authors.forename: Junfeng
authors.initials: J
authors.lastname: Geng
authors.forename: Kelong
authors.initials: K
authors.lastname: Ma
authors.forename: Jian
authors.initials: J
authors.lastname: Yu
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Sun
authors.forename: Zhenya
authors.initials: Z
authors.lastname: Shen
authors.forename: Guoliang
authors.initials: G
authors.lastname: Bao
authors.forename: Yinming
authors.initials: Y
authors.lastname: Chen
authors.forename: Hongyu
authors.initials: H
authors.lastname: Zhang
authors.forename: Yinghua
authors.initials: Y
authors.lastname: He
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Luo
authors.forename: Xu
authors.initials: X
authors.lastname: Feng
authors.forename: Jingde
authors.initials: J
authors.lastname: Zhu
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000328:Adult; D000368:Aged; D051017:Apoptosis Regulatory Proteins / Q000235:genetics; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000473:pathology; D002681:China; D019175:DNA Methylation; D064550:Death-Associated Protein Kinases; D047628:Estrogen Receptor alpha / Q000235:genetics*; D005260:Female; D017491:Genes, APC; D019942:Genes, p16; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D008668:Metallothionein / Q000235:genetics; D008875:Middle Aged; D009367:Neoplasm Staging; D051059:PTEN Phosphohydrolase / Q000235:genetics; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000235:genetics*
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D051017:Apoptosis Regulatory Proteins; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D018398:Homeodomain Proteins; C522807:Hoxc9 protein, human; C499629:MT1G protein, human; C411762:RASSF1 protein, human; D025521:Tumor Suppressor Proteins; D008668:Metallothionein; C579096:DAPK1 protein, human; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human