Public release date: 3-Jun-2013 [ | E-mail | Share ]
Contact: John Easton john.easton@uchospitals.edu 773-795-5225 University of Chicago Medical Center
A high percentage of African-American women with breast cancer who were evaluated at a university cancer-risk clinic were found to carry inherited genetic mutations that increase their risk for breast cancer.
The finding suggests that inherited mutations may be more common than anticipated in this understudied group and may partially explain why African-Americans more often develop early onset and "triple-negative" breast cancer, an aggressive and difficult-to-treat form of the disease.
It also demonstrates the potential benefits of increased access to genetic counseling and testing for women with breast cancer and their close relatives. Through these services, family members who are found to share the same genetic risk factor for breast cancer can be offered personalized strategies for early detection and prevention of breast cancer.
"Our study confirms the importance of screening for mutations in breast cancer susceptibility genes in all African-American breast cancer patients diagnosed by age 45, those with a family history of breast or ovarian cancer, or with triple-negative breast cancer before age 60," said study author Jane Churpek, MD, assistant professor of medicine at the University of Chicago Medicine. "This could identify at-risk family members in time for life-saving interventions and help prevent future cancers for the patients as well."
The study, to be presented June 3 at the 2013 Annual Meeting of the American Society of Clinical Oncology in Chicago, is the first comprehensive screening among African-American women of all 18 known breast cancer susceptibility genes using new methods called targeted genomic capture and next-generation sequencing.
The researchers found that 56 of the 249 women studied (22 percent) at the University of Chicago Medicine's Cancer Risk Clinic had inherited at least one damaging mutation that increased their risk of breast cancer. Twenty-six of the patients had a BRCA1 mutation. Another 20 patients had a BRCA2 mutation. Twelve women inherited mutations in other genes: CHEK2, PALB2, ATM, and PTEN. Two women inherited mutations in two different genes.
Patients most likely to carry a mutation were those diagnosed with a second primary tumora second cancer that developed independently from the first; 49 percent of those women carried an inherited breast cancer-associated gene mutation. Other groups highly likely to carry inherited mutations included those with a close relative who had either breast or ovarian cancer (30 percent), those with triple-negative breast cancer (30 percent), and those who were diagnosed with breast cancer by age 45 (27 percent).
Identifying these inherited mutations can have a significant impact. Whereas 12 percent of women in the general population will develop breast cancer by age 80, those carrying a harmful mutation in BRCA1 or BRCA2 have a 37 to 85 percent lifetime risk of developing breast cancer. Mutations in these genes provide the best tools for tailoring risk-reducing interventions.
More:
Mutations in susceptibility genes common in younger African American women with breast cancer