The methylation analysis of CDH1 promoter and enhancers was performed on eight GC cell lines (NCI-N87, KATO-III, SNU-5, SNU-1, AKG, GK2, KKP and MKN-74), on germline DNA from peripheral blood of 6 healthy individuals and 20 HDGC CDH1-negative patients (15 with DGC and 5 with LBC) and on gastric normal and tumor tissues from 13 sporadic GC patients (10 with IGC, 1 with DGC, 1 with mucinous GC and 1 with mixed GC). This evidence concerns the gene CDH1 and CDH1-related diffuse gastric and lobular breast cancer syndrome.