ERBB2 and invasive ductal breast carcinoma: We found the DFS of the HER2 IHC 2+ group was significantly better than that of the HER2 IHC 1+ and IHC 0 group in the invasive ductal carcinoma subgroup (HR 0.72, 95% CI: 0.52–1.00, p = 0.050), the T1–T2 subgroup (HR 0.71, 95% CI: 0.51–0.99, p = 0.045), the grade 2 subgroup (HR 0.64, 95% CI: 0.43–0.96, p = 0.030), and the lymphovascular invasion subgroup (HR 0.55, 95% CI: 0.31–0.97, p = 0.039) (Figure 3).