Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Dis Markers. 2012;32(3):195-202. doi: 10.3233/DMA-2011-0877.
Most cases of gastric cancer (GC) are not diagnosed at early stage which can be curable, so it is necessary to identify effective biomarkers for its diagnosis and pre-warning. We have used methylated DNA immunoprecipitation (MeDIP) to identify genes that are frequently methylated in gastric cancer cell lines. Promoter regions hypermethylation of candidate genes were tested by methylation-specific polymerase chain reaction (MSP) in serum samples, including GC (n=58), gastric precancerous lesions (GPL, n=46), and normal controls (NC, n=30). Eighty two hypermethylated genes were acquired by array analysis and 5 genes (BCAS4, CHRM2, FAM5C, PRAC and MYLK) were selected as the candidate genes. Three genes (CHRM2, FAM5C and MYLK) were further confirmed to show methylation rates increased with progression from NC to GPL, then to GC. There was obvious decrease in detection of FAM5C and MYLK hypermethylation, but not CHRM2, from preoperative to postoperative evaluation (P< 0.001). Combined detection of FAM5C and MYLK hypermethylation had a higher sensitivity in GC diagnosis (77.6%,45/58) and pre-warning (30.4%,14/46) than one single gene detection and also had a high specificity of 90%. The combined hypermethylated status of FAM5C and MYLK correlated with tumor size (P<0.001), tumor invasion depth (P=0.001) and tumor-node-metastasis (TNM) stage (P=0.003). Hypermethylated FAM5C and MYLK can be used as potential biomarkers for diagnosis and pre-warning of GC.
大多数胃癌（GC）病例在可治愈的早期阶段并未被诊断出来，因此有必要确定有效的生物标志物用于其诊断和预警。我们使用甲基化 DNA 免疫沉淀（MeDIP）来鉴定在胃癌细胞系中频繁甲基化的基因。通过甲基化特异性聚合酶链反应（MSP）在血清样本中测试候选基因的启动子区域超甲基化，包括 GC（n=58）、胃癌前病变（GPL，n=46）和正常对照（NC，n=30）。通过阵列分析获得了 82 个高甲基化基因，选择了 5 个基因（BCAS4、CHRM2、FAM5C、PRAC 和 MYLK）作为候选基因。进一步证实了 3 个基因（CHRM2、FAM5C 和 MYLK）随着从 NC 到 GPL 再到 GC 的进展，其甲基化率增加。从术前到术后评估（P<0.001），FAM5C 和 MYLK 甲基化的检测明显减少。但 CHRM2 则不然。FAM5C 和 MYLK 联合检测在 GC 诊断（77.6%，45/58）和预警（30.4%，14/46）中的敏感性高于单个基因检测，特异性也高达 90%。FAM5C 和 MYLK 的联合高甲基化状态与肿瘤大小（P<0.001）、肿瘤侵袭深度（P=0.001）和肿瘤-淋巴结-转移（TNM）分期（P=0.003）相关。高甲基化的 FAM5C 和 MYLK 可作为 GC 诊断和预警的潜在生物标志物。
