Frequent promoter methylation of CDH1 in non-neoplastic mucosa of sporadic diffuse gastric cancer.

BACKGROUND/AIM To identify promoter methylation as a major silencing mechanism in potential precursor lesions of sporadic diffuse gastric cancer (DGC), we investigated promoter methylation of CDH1 (E-Cadherin gene) in a series of DGCs and matched normal mucosa. MATERIALS AND METHODS The extent of CDH1 gene promoter methylation was explored using methylation-specific polymerase chain reaction (MSP) and pyrosequencing (PS) in 72 DGCs with a matched pair of normal mucosa. RESULTS MSP and PS revealed CDH1 promoter methylation in 73.6% (53/72) and 77.8% (56/72) of DGC samples, respectively. PS detected CDH1 methylation in 70.8% (51/72) and 72.2% (52/72) of matched normal mucosa from adjacent and remote foci, respectively. In comparison, CDH1 promoter methylation was detected in 12/24 normal gastric mucosa samples without DGC, and this difference was statistically significant (p=0.016). CONCLUSION The current study showed that the majority of DGC cases demonstrated concurrent CDH1 promoter methylation in tumor tissues and in non-neoplastic mucosa.