Reply to “Inadequate representation of individuals of African ancestry in pharmacogenetics of tamoxifen research”

We acknowledge the points raised by Nthontho et al.¹ We concur with the statement that there is an “inadequate representation of individuals of African ancestry in pharmacogenetics of tamoxifen research.” Indeed, the complex genetic and disease landscape across the continent necessitate that tamoxifen pharmacogenetic studies encompass diverse populations across the entirety of Africa.

Furthermore, we agree with the observation that the focus of tamoxifen pharmacogenetic studies should be directed toward the inclusion of variants relevant to African populations, and not only investigating genetic variation in CYP2D6 but also incorporating other genes coding for enzymes participating in the different pathways of tamoxifen disposition, including phase II genes coding for sulfotransferases (SULTs), uridine 5′-diphospho-glucuronosyltransferases (UGTs) and other cytochrome P450 (CYP) genes. The benefit of including variants common to Africans in pharmacogenetic studies is already evident in research that have improved our understanding of the variability in treatment response in African patients.^{2, 3} As mentioned by Nthontho et al.,¹ findings from similar studies could serve as a foundation for advancing tamoxifen pharmacogenetic research.

For tamoxifen pharmacogenetic studies to be informative, research should be conducted through well-designed clinical studies that incorporate big data to include as many populations as possible across the continent, capturing a wide range of genetic and environmental biomarkers common to African populations. Leveraging “omics” technologies will significantly enhance our understanding of pharmacogenetics in African populations. As highlighted in the response, there is a critical need for funding and organizational support to advance not only tamoxifen pharmacogenetic research but also pharmacogenomics research in Africa.

The African Pharmacogenomics Consortium/Network (APN) was established to address the lack of pharmacogenomics studies in Africa and among African populations.⁴ The APN aims to strengthen the capacity for research and implementation of pharmacogenomics by consolidating the continent's expertise and technological platforms. Achieving this requires strategic collaboration among African researchers and the involvement of international partners.

We advocate for increased collaboration within Africa to enable the continent to advance in pharmacogenomic research. By fostering these partnerships, Africa can build its capacity, contribute valuable insights to the global field, and become a leading force in pharmacogenomics.

No funding was received for this work.

The authors declared no competing interests for this work.