Investigators have identified two genetic risk loci that may be associated with an increased risk of breast cancer for Black South African women, according to findings from a genome-wide association study published in Nature Communications.
The two risk loci were between UNC13C and RAB27A on chromosome 15 (rs7181788, P = 1.01 × 10−08), and in gene USP22 on chromosome 17 (rs899342, P = 4.62 × 10−08).
“These genes have not been associated with the disease before, which is an important advance in understanding breast cancer risk and biology in women of African ancestry,” stated lead study author Mahtaab Hayat, PhD, of the Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
Study Background and Methods
Previous genetics research into breast cancer risk has centered on women of European and Asian ancestry or African American women, who are mostly descendent from West African countries. Previous polygenic risk scores have not been helpful for South African women, demonstrating a need for greater study and genomic research in this population.
“This is because most polygenic risk scores were developed in European populations, and their inaccuracy in African populations highlights the urgent need for ancestry-specific tools in cancer risk prediction,” stated study author Jean-Tristan Brandenburg, a researcher at the Sydney Brenner Institute for Molecular Bioscience, University of the Witwatersrand.
The investigators conducted a genome-wise association study of Black South African women, including 2,485 women with breast cancer from the Johannesburg Cancer Study and 1,101 matched controls from the Africa Wits-INDEPTH Partnership for Genomic Research Study.
The findings of the study were not replicated among populations of patients with breast cancer of West African ancestry, which the study authors noted was suggestive of genetic heterogeneity in different African populations. Only 0.79% of data variance could be explained with a polygenic risk model for patients with breast cancer of European ancestry.
The investigators stressed that further genomic research is needed in this population to confirm the findings, but with further confirmation, these genes could potentially become targets for new targeted therapies and help to identify more aggressive cancers.
Disclosure: For full disclosures of the study authors, visit nature.com.
