ERBB2 and breast carcinoma: A recent study demonstrated that varying subtypes of TNBC may respond differently to neoadjuvant therapy.5 It is likely that varying subtypes within each of the conventional types of breast cancer (hormone receptor (HR) positive, HER2+, TNBC) may have different clinical and prognostic features, and AR expression may factor into this heterogeneity, across breast cancer subtypes.