Results: In HER2 positive breast cancer patients, those exhibiting histological grade III, HER2 IHC 3+ expression, absence of lymphovascular invasion, clinical N1 stage, prominent and hypervascular tumor CDFI signal pre-NAT, and achievement of breast pathological complete response (bpCR) following NAT were significantly more likely to achieve ypN0 status. The gene discussed is ERBB2; the disease is breast carcinoma.