Abstract
To extend earlier observations of germline E-cadherin mutations in kindreds with an inherited susceptibility to diffuse gastric cancer, we searched for germline E-cadherin mutations in five further families affected predominantly by diffuse gastric cancer and one family with a history of diffuse gastric cancer and early-onset breast cancer. Heterozygous inactivating mutations were found in the E-cadherin gene in each of these families. No mutation hotspots were identified. These results demonstrate that germline mutation of the E-cadherin gene is a common cause of hereditary diffuse gastric cancer and suggest a role for these mutations in the incidence of breast cancer.