These statistics complement data in a recent molecular analysis of breast tumors in a Nigerian population, in whom 68% of tumors tested were ER negative, 25% were HER2 positive, and ER-positive tumors were biologically more aggressive.15 In the United States, subtype prevalence is notably different (33% vs ~20% ER negative; 17% vs ~15% HER2 positive for black and white, respectively).16 This significant difference in subtype prevalence and aggressiveness of cancer in African populations illustrates the need to know biomarker status for treatment. Here, ESR1 is linked to cancer.