CDH1 (E-Cadherin) Mutation and Gastric Cancer: Genetics, Molecular Mechanisms and Guidelines for Management.

Introduction: Germline mutation in CDH1 (E-cadherin) tumor suppressor gene is associated with hereditary diffuse gastric cancer (HDGC) and lobular breast cancers (LBC). E-Cadherin protein is necessary for physiological signaling pathways, such as cell proliferation, maintenance of cell adhesion, cell polarity and epithelial-mesenchymal transition. Dysregulation leads to tumor proliferation, invasion, migration and metastases. We review current perspectives in CDH1 genetics with molecular mechanisms and also discuss management strategies for this aggressive form of gastric cancer.

Methods: Relevant articles from PubMed/Medline and Embase (1994-2019) were searched and collected using the phrases "Hereditary diffuse gastric cancer, Familial gastric cancer, mutation, E-Cadherin, Lobular breast cancer, Prophylactic total gastrectomy".

Results: Current guidelines suggest maintaining a high degree of suspicion of hereditary etiology and recommend testing for mutations in patients with familial clustering of HDGC and LBC, especially onset at an early age (before 40 years). In families lacking CDH1 mutations but with high suspicion for hereditary predisposition, testing of CTNNA1 and other closely related HDGC susceptibility genes could be considered. Prophylactic total gastrectomy is recommended for individuals with identified pathogenic germline variants. Endoscopic surveillance with biopsies is recommended for those choosing to delay prophylactic gastrectomy.

Conclusion: Mutation or transcriptional silencing of the is associated with familial diffuse gastric cancer. Further studies on the expression and the alteration in the proteins in the E-cadherin pathways may serve as biomarkers for early detection; stratify risk and selection of appropriate therapy in these families. Until then prophylactic total gastrectomy is recommended for individuals with mutations and family history of diffuse gastric cancer. Endoscopic surveillance and biopsies by experienced gastroenterologists is recommended for those choosing not to have prophylactic gastrectomy and in individuals with variants.