Studies have shown that patients with small tumors of HER2+, LN- still have a higher risk of recurrence compared to patients with small tumors of HER2- (52); for these patients, further chemotherapy can be added to trastuzumab; studies showed that early breast cancer patients with TC+H regimen had 2-year disease-free survival(DFS)and overall survival (OS) rates of 97.8% and 99.2% (52); Therefore, the TC+H regimen can be considered for low-risk patients with T1N0, HER-2-positive disease. The gene discussed is ERBB2; the disease is breast carcinoma.