Although the complexity of the tumor microenvironment in human pathology cannot be entirely mimicked by in vivo studies, future functional studies on gastric adenocarcinoma cell lines are clearly needed to shed light on the connections with the cell cycle and on the functionality of E-cadherin itself through its intracytoplasmic pathways towards and from the membrane-bound isoforms. This evidence concerns the gene CDH1 and gastric adenocarcinoma.