ERBB2 and breast carcinoma: When considering the intrinsic subtypes of breast cancer according to the immunohistochemical status, superior PFS was found in the surgical group of luminal subtype (ER/PR positive, HER2 negative), but no statistical significance was proven (HR: 0.63, 95% CI: 0.86‐2.92, P = .13, Supplement Figure S2).