Lower LINE-1 methylation is associated with promoter hypermethylation and distinct molecular features in gastric cancer.

To investigate the associations between methylation, an indicator for genome-wide hypomethylation, molecular and clinicopathological characteristics of gastric cancer (GC) patients. methylation statuses were examined in paired cancerous, non-neoplastic mucosa from 217 GC and gastric mucosa from separate group of 224 noncancer patients. CpG island methylator phenotype, and mutation, methylation status and promoter hypermethylation of GC related and -related genes were examined. Lower methylation was observed in primary GC compared with non-neoplastic gastric mucosa and associated with CpG island methylator phenotype, mutation, methylation and promoter hypermethylation of GC related and -related genes. Lower methylation correlates specific molecular subtypes and promoter hypermethylation in GC.