ERBB2 and breast cancer: The oncotype DX (ODX) recurrence score (RS) (Exact Sciences., Madison, WI) is a validated prognostic and predictive tool to estimate patient risk of distant breast-cancer recurrence and guide the use of adjuvant chemotherapy in hormone receptor-positive (HR+) human epidermal growth factor receptor-2 negative (HER2–), early-stage breast cancer1,2.