A recent observational study published in npj Breast Cancer in March 2026 reveals that tumor biology is the primary driver of early breast cancer recurrence, not race. Data shows that Black patients have more than double the rate of aggressive basal-type tumors compared to White patients (11.0% vs. 4.8%). While hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer is common, Black women suffer a 40% higher mortality rate that previous research into socioeconomic status has not fully explained, creating a critical clinical gap. Identification of racial disparities across MammaPrint and BluePrint subtypes in HR + HER2- breast cancer. npj Breast Cancer (2026).