Study aims to identify genes that are unique to breast cancer in African American women
During the “Jewels in Our Genes” study several years ago, Heather Ochs-Balcom and her team pinpointed four locations in the genome of African American women that may contain undiscovered genes that contribute to hereditary breast cancer.
The University at Buffalo scientist has received a new federal grant to further that work with a follow-up study.
Ochs-Balcom, Ph.D., an associate professor of epidemiology and environmental health in UB’s School of Public Health and Health Professions, was awarded $457,660 from the National Cancer Institute, part of the National Institutes of Health.
In this new study, Ochs-Balcom and her colleagues from the University of Southern California, Case Western Reserve University and the National Institute of Environmental Health Sciences (NIEHS) will zero in on the four regions previously identified in “Jewels in Our Genes,” studying them in larger external datasets.
The study will look at more than 18,500 African American women, including those who have been diagnosed with breast cancer, as well as women who are cancer-free.
“We hope to identify genes that are unique to African Americans that might explain differences in breast cancer risk,” Ochs-Balcom said. “If we see significant genetic variants in these regions in these larger datasets, that will help us to not only narrow down the regions to specific genes, but also may lead to new breast cancer gene discovery.”
Such a discovery would be huge. Young African American women experience higher rates of, and deaths due to, breast cancer compared to European Americans. The reasons for these disparities are complex, according to Ochs-Balcom.
“Jewels in Our Genes” (2009-14) was the first published breast cancer linkage study in African Americans. In contrast, the first linkage study for breast cancer in white women and the subsequent identification of BRCA1 – the gene whose mutations are linked to hereditary breast cancer – was conducted in the early 1990s.
“Our study will provide evidence for whether other genes not yet discovered are related to familial breast cancer risk in African Americans, a hypothesis we have been pursuing for years,” Ochs-Balcom said.
This new study will build off the identification of the four novel linkage peaks discovered in “Jewels in Our Genes.”
Linkage peaks are the significant outcome or results from the researchers’ previous linkage study in African American families.
“A linkage study is an approach that can help to identify specific parts of chromosomes that are harboring undiscovered risk alleles and being passed through families,” Ochs-Balcom explained.
The next step is called fine mapping. It’s a process in which the four previously identified linkage peaks will be studied in finer detail using external, independent samples to see if there are undiscovered risk alleles.
In addition, Ochs-Balcom and her colleagues will conduct a genome-wide association study – which searches the genome for small variations that commonly occur in people with a particular disease – that integrates family-based data with population-based data from the Women’s Health Initiative.
“Ultimately, we hope to identify new genes that are associated with breast cancer risk that can be used to identify women at risk long before they develop breast cancer so that their cancers can be prevented,” Ochs-Balcom said. “In a similar vein, we hope that new genes that we discover can tell us more about how breast cancer develops and how different breast cancer types are unique.”