Breast cancer is the most common cancer among women worldwide and a leading cause of cancer-related deaths in sub-Saharan Africa. While known risk factors include age, obesity, alcohol consumption, and family history, genetic predisposition also plays a major role. Recent research has uncovered unique genetic variants that influence breast cancer risk in African women, paving the way for more accurate diagnosis and prevention strategies.
Genome-wide association studies (GWAS) scan the entire DNA of individuals to identify genetic differences linked to diseases. Since their introduction in 2005, these studies have advanced understanding of cancer and other illnesses, leading to the development of polygenic risk scores. These scores estimate an individual’s risk of disease based on multiple genetic variants. However, most GWAS research has focused on populations of European ancestry, leaving African populations underrepresented despite their high genetic diversity.
To address this gap, researchers conducted the first large-scale GWAS of breast cancer in sub-Saharan Africa. The study analyzed DNA samples from 2,485 women with breast cancer and 1,101 women without, all residents of Soweto, South Africa. Using a DNA chip designed by the H3Africa consortium to capture African genetic variants, the researchers identified two novel genomic variants near the RAB27A and USP22 genes. These genes are linked to cancer cell growth, tumor progression, and metastasis. Importantly, these variants had not been associated with breast cancer in non-African populations.
The team also tested European-derived polygenic risk scores on the African dataset. The results revealed limited predictive power, confirming that tools developed for European populations are less effective in African contexts. This finding underscores the importance of population-specific research to improve cancer prediction and care.
Although the study involved fewer than 4,000 samples, its findings mark a significant milestone. Larger genetic studies, often involving more than 200,000 participants, have excluded African populations. Expanding research across the continent is crucial for developing accurate risk assessment tools tailored to local populations.
The discoveries hold promise for earlier detection and prevention. By identifying women at higher genetic risk, healthcare providers can recommend regular check-ups and preventive interventions, reducing the likelihood of late-stage diagnoses. Further research will clarify how the identified genes increase risk and enhance the accuracy of prediction models.
This study represents a critical step toward inclusive global cancer research, ensuring that African women benefit from precision medicine in breast cancer care.
