ABSTRACT
Objective To study the changes of CDH1 gene promoter CpG island methylation and its clinical significance in patients with esophagus and stomach double primary carcinoma(ESDC).Methods The expression of CDH1 gene methylation in cancerous tissues and adjacent cancerous tissues in 18 cases of ESDC were detected using methylation-specific PCR method. Results Eighteen patients were endoscopically diagnosed as ESDC between Jan. 2007 and Sep. 2009 in the 4th Hospital Affiliated to Hebei Medical University. The positive methylation of CDH1 gene in tissues of esophageal squamous cell carcinoma (ESCC)and adjacent cancer were 66.7% and 33. 3%, respectively, with significant difference (χ2= 4. 167, P = 0. 031). Whereas the positive methylation of CDH1 gene in tissues of gastric carcinoma (GA) and adjacent cancer were 77.8% and 44.4%, respectively, without statistical difference (χ2=1.786, P= 0. 180). There was no significant difference (P=0. 500) in positive rate of CDH1 gene methylation between ESCC tissues and GA tissues in same individual with ESDC. For 18 patients with ESDC, consistent change of CDH1 methylation in tissues of two kinds of cancers was found in 16 patients with a total agreement of 88.9 % (positive agreement of 66.7 % and negative agreement of 22. 2%). Statistical analysis showed a significant correlation between two groups (P = 0. 005). Conclusion In patients with ESDC, there is a high consistency of CDH1 methylation change, between ESCC and GA,which suggests that two kinds of cancer may have similar risk factors and molecular mechanisms.