Germline Genetic Testing for Hereditary Diffuse Gastric Cancer (CDH1, CTNNA1)

Hereditary Diffuse Gastric Cancer (HDGC, sometimes called signet ring gastric cancer) is an autosomal dominant syndrome characterized by the development of diffuse gastric cancers. CDH1 is a tumor suppressing gene that encodes the cell-to-cell adhesion protein E-cadherin. Germline variants in the CDH1 gene have been associated with an increased risk of developing HDGC and lobular breast cancer. Testing for CTNNA1 variants has also been proposed for individuals with or at risk for HDGC. Knowledge of variant status in individuals at potentially increased risk may impact health care decisions to reduce risk.