ERBB2 and breast cancer: Personalized approaches to breast cancer treatment are increasingly guided by expensive, lab‐based genomic testing such as the Oncotype DX (ODX) Breast Recurrence Score Test, a prognostic and predictive 21‐gene assay which both estimates risk of recurrence and predicts the benefit of adjuvant chemotherapy in women with hormone receptor‐positive (HR+), HER2‐negative, early‐stage breast cancer (eBC) [1].