ERBB2 and breast cancer: For TN and HR−/HER2+ disease, young Black women had slightly elevated risks in some stages that were mostly explained by treatment and insurance status, except for stage I HR−/HER2+ where a four times greater hazard of breast cancer-specific death was estimated after adjustment for age, year, grade, treatment, and insurance status (HR: 4.09; 95% CI: 1.50, 11.15).