Background: The cell surface glycoprotein, E-Cadherin (CDH1) is a key regulator of adhesive properties in epithelial cells. Germline mutations in CDH1 are well-established as the defects underlying the Hereditary Diffuse Gastric Cancer (HDGC)syndrome: an increased risk of lobular breast cancer (LBC) has been described in HDGC kindreds. However, germline CDH1 mutations have not been described in LBC patients outside of HDGC families. We sought to investigate the frequency of germline CDH1 mutations in LBC patients with early onset disease or family histories of breast cancer without DGC.
Methods: Germline DNA was analyzed in 23 women with invasive lobular or mixed ductal and lobular breast cancers who had at least one close relative with breast cancer or had themselves been diagnosed before age 45, had tested negative for a germline BRCA1 or BRCA2 mutation, and reported no personal or family history of diffuse gastric cancer. The full coding sequence of CDH1 including splice junctions was PCR amplified and screened for mutations using DHPLC and sequencing.
Results: A novel germline CDH1 truncating mutation in the extracellular portion of the protein (517insA) was identified in one subject who had lobular breast cancer at age 42 and a first degree relative with invasive lobular breast cancer.
Conclusions: Germline CDH1 mutations can be associated with invasive lobular breast cancer in the absence of diffuse gastric cancer. The finding, if confirmed, may have implications for management of individuals at risk for this breast cancer subtype, and compels clarification of the cancer risks in the syndrome.
- Lobular Breast Cancer
- familial breast cancer
- germline mutations