A study by researchers at the University of the Witwatersrand has identified two genetic variants that increase the risk of breast cancer among African women — findings that could transform how the disease is screened and managed across the continent.
The study, the first genome-wide association analysis of breast cancer in a sub-Saharan African population, discovered genetic differences near the RAB27A and USP22 genes that were strongly associated with breast cancer risk in Black South African women. These variants have never before been linked to breast cancer in non-African populations.
Researchers compared DNA samples from 2,485 women diagnosed with breast cancer and 1,101 women without the disease, all from Soweto, South Africa.
The analysis used advanced DNA technology designed by the H3Africa consortium, which captures genetic variations unique to African populations.
“Our findings underscore the importance of studying African genetic diversity to better understand disease risks,” said Dr. Jean-Tristan Brandenburg of the Sydney Brenner Institute for Molecular Bioscience. “What we see in European populations doesn’t always apply in Africa.”
Why It Matters
Breast cancer remains the most common cancer among women worldwide and a leading cause of cancer-related deaths in sub-Saharan Africa.
Yet, most genetic studies on breast cancer risk have focused on people of European ancestry, leaving major gaps in understanding how the disease affects African populations.
When researchers applied European-derived polygenic risk scores—a genetic tool used to predict breast cancer risk—to the African dataset, they found the predictions were far less accurate.
This highlights the need for population-specific genetic data to improve early detection and prevention strategies in Africa.
The study’s authors say the results pave the way for better screening and prevention tools tailored for African women, allowing doctors to identify high-risk individuals earlier.
However, they also called for larger genetic studies to expand the data pool. The current research analyzed fewer than 4,000 samples, compared to over 200,000 cases and controls typically used in similar studies in Western countries.
The researchers are now participating in Confluence, a global project investigating the genetics of breast cancer across multiple populations, including African ones.
“If we can identify those at greatest risk, we can offer preventive measures and more frequent check-ups,” said Professor Christopher Mathew, co-author of the study. “This could help save countless lives.”
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