The Kaplan–Meier curve showed that the best DFS rate was found for HER2+ BC patients with ypT0-ypT1, ypN0, post-NACT stage 0–I (P = 0.013, P = 0.048 and P = 0.016, respectively), and with low RTC, tumoral pCR, lymph nodal pCR, low lymph node ratio, pre-NACT AR positivity, low post-NACT ki67 expression, high pre-NACT TILs and more frequently right-sided (P = 0.00031, P = 0.0041, P = 0.020, P = 0.00036, P = 0.011, P = 0.00072, P = 0.038 and P = 0.042, respectively) (SI Fig. 1). This evidence concerns the gene MKI67 and breast cancer.