Ethnicity, Immunity, and Outcomes: Biology versus Socioeconomic Status.

Substantial advances in our understanding of breast cancer disease biology have led to marked improvements in cancer outcomes over the past two decades. These advances have largely focused on women from developed, high-income countries and as a result, significant disparities exist. In this issue, Bauer and colleagues provide new insight into the breast cancer immune microenvironment from women across geographic regions in sub-Saharan Africa, despite inherent infrastructure limitations. The study amassed data from 1,497 women from sub-Saharan Africa, and 117 women from Germany with breast cancer, suggesting regional variation in immune composition but with no significant prognostic impact. These important findings require validation in large, codesigned prospective studies to fully understand the impact of biology, ethnicity, and socioeconomic status on breast cancer outcomes. See related article by Bauer et al., p. 720 (2) .