According to the results of a study conducted in Iceland, a specific mutation of the BARD1 gene increases the risk of developing breast cancer. These results were published in the journal PLoS Medicine.
Inherited mutations in two genes-BRCA1 and BRCA2-have been found to greatly increase the lifetime risk of developing breast and ovarian cancer. However, many individuals with familial breast cancer lack mutations in these genes, and researchers continue to search for other inherited genetic mutations that increase the risk of breast cancer.
The BARD1 gene produces a protein that interacts with the BRCA1 protein to carry out important cellular functions. The role of BRCA1 mutations in breast cancer prompted interest in the role of BARD1 mutations. One BARD1 variant in particular-known as Cys557Ser-has been reported to be more common in families with breast cancer.
To explore the role of this particular BARD1 variant in breast cancer, researchers in Iceland conducted a study among roughly 1000 individuals with breast cancer and 700 individuals without breast cancer.
- The Cys557Ser variant was more common in individuals with breast cancer than in individuals without breast cancer. The Cys557Ser variant was identified in 5.4% of patients with breast cancer and 3.1% of individuals without breast cancer. The BARD1 Cys557Ser variant may account for 2.5% of breast cancers in Iceland.
- The Cys557Ser variant was even more common in breast cancer patients with a family history of breast cancer, early onset breast cancer, or multiple breast cancers. However, many women with the BARD1 Cys557Ser variant did not have a distinctive family history of breast cancer.
- The Cys557Ser variant increased the risk of breast cancer in women with and without the common Icelandic BRCA2 mutation (BRCA1 mutations are uncommon in Iceland).
The researchers conclude that the BARD1 Cys557Ser variant increases the risk of breast cancer, and that this increased risk applies to women with and without the most common BRCA2 mutation in Iceland.
Reference: Stacey SN, Sulem P, Johannsson OT et al. The BARD1 Cys557Ser Variant and Breast Cancer Risk in Iceland. PLoS Medicine . 2006;3(7):e217.