The study included 179 women who had been diagnosed with breast cancer and 76 of their sisters who never had the disease. "Perhaps the most important motivating factor in their decision to participate in our study," says Heather Ochs-Balcom, "was the potential to prevent suffering in their daughters and granddaughters." (Credit: iStockphoto)

African American health

Breast cancer genes may be unique to African Americans

African-American women from the same family who have breast cancer may share previously unknown DNA anomalies in addition to BRCA1, BRCA2, new research shows.

“The discovery of these regions supports our hypothesis that there are still undiscovered breast cancer genes that may be unique to African Americans,” says Heather Ochs-Balcom, a genetic epidemiologist at the University at Buffalo.

“We can now focus on these specific chromosomes to learn if they house genetic mutations linked to breast cancer.

Undiscovered mutations

“We also need to determine whether those mutations are found in other racial groups or if they are unique to African Americans. If they are unique, it could explain why young African-American women have a higher risk of pre-menopausal breast cancer compared to other groups,” she says.

“Our study used linkage analysis, a powerful tool that helps to detect the chromosomal location of disease genes by examining genetic markers across the entire human genome. Our family-based gene hunt is similar to the groundbreaking study among women with European ancestry done in the early 1990s that led to the discovery of BRCA1 and BRCA2 gene mutations, which greatly increase susceptibility to breast and ovarian cancer.”

African-American women can also carry the BRCA mutations, but Ochs-Balcom suspects there may be additional, undiscovered mutations linked to breast cancer in this population.

“Family studies like this one have been difficult to conduct in the past,” Ochs-Balcom says, “in part because it’s difficult to get multiple family members to commit the time needed to participate. We found here that approaching the recruitment of African Americans by using a multi-pronged approach that included collaboration from our community partnerships greatly facilitated success.

Risk of early-onset cancers

African-American women have a higher incidence of pre-menopausal breast cancer and a higher breast cancer mortality rate than European Americans. They are also more likely to develop early-onset cancers that are aggressive and difficult to treat. Some of these may be caused by unknown genetic anomalies that if found, could lead to early screening, detection, and treatment.

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The study, conducted between 2009 and 2014, is the subject of two recent papers published in the journal Cancer, Epidemiology, Biomarkers and Prevention and in the Journal of Community Genetics.

Researchers examined the DNA of 106 African-American families not known to carry BRCA mutations tied to hereditary breast-ovarian cancer syndrome. Participants included 179 women who had been diagnosed with breast cancer and 76 of their sisters who never had the disease.

“Perhaps the most important motivating factor in their decision to participate in our study,” says Ochs-Balcom, “was the potential to prevent suffering in their daughters and granddaughters.”

Researchers from Case Western Reserve University School of Medicine, Roswell Park Cancer Institute, and Lina the Icahn School of Medicine at Mount Sinai Hospital are coauthors of the study, which received funding from the Susan G. Komen for the Cure Foundation.

Source: University at Buffalo

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