Researchers identified novel genetic mutations that are linked to hereditary diffuse gastric cancer (HDGC), with these mutations being due to both independent mutational events and common ancestry.
HDGC is caused by mutations in the gene CDH1, and is characterized by an increased risk for diffuse gastric cancer and lobular breast cancer. Researchers at the BC Cancer Agency conducted a study to assess the frequency of mutations in the CDH1 gene and whether these mutations occurred due to independent mutational events or common ancestry.
The study included 38 families diagnosed clinically with HDGC, who were then analyzed for CDH1 mutations. Thirteen mutations, six novel, were identified in 15 of the 38 families. Two families from this study plus two additional families carrying the novel 2398delC mutation shared a common haplotype, suggesting a founder effect. All four families originate from the southeast coast of Newfoundland.
Within these four families, the cumulative risk by age 75 years in mutation carriers for clinically detected gastric cancer was 40% for males and 63% for females, and the risk for breast cancer in female mutation carriers was 52%.
“Our results confirm that between 30% and 40% of families with a positive family history of gastric cancer and more than 50% of families with two diffuse gastric cancer cases diagnosed prior to age 50 years will carry germline mutations in the CDH1 gene,” the researchers write. The study is published in the June 6 issue of JAMA.