ERBB2 and breast cancer: For patients with grade II (P < 0.0001), grade III (P < 0.01), HoR + /HER2 + (P < 0.01), HoR-/HER2 + (P < 0.0001), and HoR/HER2- (P < 0.0001) T1b BC (Fig. 1A, B, C, D and E), adjuvant chemotherapy had beneficial effects on OS.