Genetic and Epigenetic Alterations of Regulatory Regions in Hereditary and Sporadic Gastric Cancer.

E-cadherin is a key player in gastric cancer (GC) and germline alterations of , its encoding gene, are responsible for Hereditary Diffuse Gastric Cancer (HDGC) syndrome. This study aimed at elucidating the role of genetic variants and DNA methylation of promoter and enhancers in the regulation of gene expression. For this purpose, we analyzed genetic variants of the gene through Next-Generation Sequencing (NGS) in a series of GC cell lines (NCI-N87, KATO-III, SNU-1, SNU-5, GK2, AKG, KKP) and the corresponding expression levels. By bisulfite genomic sequencing, we analyzed the methylation status of regulatory regions in 8 GC cell lines, in a series of 13 sporadic GC tissues and in a group of 20 HDGC -negative patients and 6 healthy controls. The NGS analysis on coding and regulatory regions detected genetic alterations in 3 out of 5 GC cell lines lacking functional E-cadherin. regulatory regions showed different methylation patterns in patients and controls, GC cell lines and GC tissues, expressing different E-cadherin levels. Our results showed that alterations in terms of genetic variants and DNA methylation patterns of both promoter and enhancers are associated with expression levels and have a role in its regulation.