Triple-Negative Breast Cancer, Stem Cells, and African Ancestry.

Triple-negative breast cancers (TNBCs) are more common among African-ancestry populations, such as African Americans and western, sub-Saharan Africans, compared with European-ancestry populations. This phenotype prevalence contributes to disparities in breast cancer outcomes between African Americans and White Americans. Breast cancer stem cells represent the tumor subpopulation involved in metastatic virulence, and ongoing research seeks to characterize the extent to which TNBC versus non-TNBC stem cells may differ. This review summarizes the existing literature regarding TNBCs and stem cells as they pertain to the burden of breast cancer among African-ancestry populations. Additional research related to variations in somatic tumor genomics between the African-American and White-American populations is also summarized. This review furthermore explores the history of insights regarding breast cancer disparities related to racial/ethnic identity, socioeconomic status, and tumor biology.