ERBB2 and breast cancer: Trastuzumab had been widely used in clinical trials, which showed an improved therapeutic effect in clinical treatment of breast cancer patients.7,25 Anti-tumor activity of Trastuzumab was mainly based on two ways: Firstly, to combine with targeted proteins (HER-2) of tumor cell, inhibiting cell signaling transduction in the cancer cells26,27; second, to activate immune system, regulating immune mechanism to kill tumor cells.28,29 Fewer adverse reactions were found in trastuzumab immunotherapy, the effect of combined chemotherapy or radiotherapy was better in clinical treatment.