Hereditary diffuse gastric cancer.

Hereditary diffuse gastric cancer (HDGC) is a cancer predisposition syndrome caused by germline mutation of the gene for the cell-to-cell adhesion protein E-cadherin. The syndrome is dominated by predisposition to the histologically diffuse, poorly differentiated form of gastric cancer. It is not associated with intestinal-type gastric cancer, but families may have an elevated risk of lobular breast cancer. Here, we review the identified families, mutations, and proposed mechanisms by which E-cadherin loss promotes tumorigenesis.