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June 04, 2024 Story by: Editor
Breast cancer remains one of the most frequently diagnosed cancers globally, including in the United States, with over 310,000 new cases anticipated this year.
Black women are often diagnosed with breast cancer at younger ages compared to white women and face a higher mortality rate from the disease. They are also twice as likely to develop a particularly aggressive form known as triple-negative breast cancer. However, most genetic studies on breast cancer have predominantly focused on women of European ancestry, overlooking the unique genetic risks faced by women of African descent.
To address this gap, a research team led by Dr. Wei Zheng from Vanderbilt University analyzed genetic data from over 40,000 women of African descent, including about 18,000 who had been diagnosed with breast cancer. This data was collected as part of the NIH-funded African Ancestry Breast Cancer Genetic Consortium, which amalgamated information from 26 studies. Most participants (85%) were African Americans, with the remainder from Barbados or Africa.
The researchers conducted a genome-wide association study (GWAS) to identify genetic variants more common in women with breast cancer than in those without. Published in Nature Genetics on May 13, 2024, this study is the largest GWAS of breast cancer in this population to date.
The study identified 12 genetic regions, or loci, associated with breast cancer, three of which were linked to the aggressive triple-negative breast cancer. Approximately 8% of the women carried two copies of risk variants across all three loci, making them 4.2 times more likely to develop triple-negative breast cancer than women with one or no copies of these variants.
Triple-negative breast cancer is particularly challenging to treat due to the absence of specific cell receptors like estrogen or HER2 receptors. The findings from this study could help researchers identify new treatment targets for this aggressive cancer type.
Additionally, the researchers confirmed many previously identified breast cancer risk variants in other populations and discovered a rare risk variant in the gene ARHGEF38, previously associated with aggressive prostate and lung cancers.
The team used their findings to develop polygenic risk scores (PRS) for assessing breast cancer risk in women of African descent. PRS, which use genomic data to estimate the likelihood of developing certain medical conditions, have historically performed poorly in predicting breast cancer risk for Black women when based on data from other populations. The new PRS, tailored to genomic data from women of African descent, showed improved predictive power for this group.
These findings could enhance breast cancer detection and treatment strategies for Black women. Further studies involving larger and more diverse populations are needed to refine these risk predictions.“We have collaborated with researchers from over 15 institutions in the U.S. and Africa to create this extensive genetic consortium,” Dr. Zheng stated. “The data collected in this consortium will continue to be an invaluable resource for researchers worldwide.” — Vicki Contie (Source: NIH)
