Multivariate analysis identified axillary rCR (OR = 17.98; 95% CI: 1.43-225.93; p = 0.025) and Ki-67 index (OR = 0.90; 95% CI: 0.82-0.99; p = 0.045) as independent predictors of axillary pCR.<h4>Conclusions</h4>Axillary rCR and Ki-67 are independent predictors of axillary pCR in HER2+ breast cancer patients treated with NAC. This evidence concerns the gene MKI67 and breast carcinoma.