OBJECTIVETo explore the association between the progression of gastric cancer and the aberrant methylation of CDH1 gene in preoperative abdominal lavage fluid.

METHODSReal-time methylation-specific polymerase chain reaction(qMSP) was used to investigate the methylation status of the CDH1 gene promoter 5'-CpG islands from preoperative abdominal lavage fluid in 92 patients with gastric cancer. The associations between methylation of CDH1 genes and clinicopathologic features and prognosis were investigated.

RESULTSAmong the 92 patients with gastric cancer, aberrant methylation of CDH1 gene was detected in 45(48.9%) patients, including total aberrant methylation in 12(13.0%) cases and partly aberrant methylation in 33(35.9%) cases. Significant associations were found between CDH1 methylation status and tumor size, growth pattern, differentiation, lymphovascular invasion, infiltration depth, lymph node metastasis, distant metastasis, and clinical staging(all P<0.05). However, there were no significant associations between CDH1 methylation status with gender, age, tumor location, or Helicobacter pylori infection(all P>0.05). The median progression-free survival was 20 months for CDH1 methylation group and 38 months for non-methylated group, and the difference was statistically significant(P<0.01). Cox model analysis revealed that CDH1 methylation status in preoperative peritoneal lavage fluid was an independent factor associated with postoperative survival in patients with gastric cancer(P=0.000, RR=332.88, 95%CI:21.71-5105.07).

CONCLUSIONSThe aberrant methylation of 5'-CpG of CDH1 gene promoter is common in gastric cancer. The examination of CDH1 methylation status of abdominal lavage should be considered in the progression of gastric cancer.