Proximal GC and GEJ adenocarcinoma are linked to gastroesophageal reflux disease and the formation of Barrett’s mucosa.71 About 10% of all GC exhibits underlying genetic predispositions.71 Genes associated with hereditary GC include, for instance, CDH1 (E-cadherin), CTNNA172,73, FBXO24, or DOT1L. 74 GC can also occur in association with other well-defined hereditary cancer syndromes, such as familial adenomatous polyposis, Cowden syndrome, Lynch syndrome, MUTYH-associated adenomatous polyposis or Li-Fraumeni syndrome.75 This evidence concerns the gene DOT1L and gastric cancer.