ERBB2 and breast cancer: However, in the HR-positive subgroup, DFS was significantly better in the HER2 3+ group compared to the HER2 2+/FISH+ group (P = 0.024).<h4>Conclusion</h4>High HER2 protein expression (IHC 3+) is a predictive factor for achieving a higher pCR rate with NAT in HER2-positive breast cancer.