Abstract: ObjectiveTo investigate the effects of aspirin combined with trastuzumab on proliferation and apoptosis of HER-2positive breast cancer cell line SKBR-3. MethodsThe SKBR-3 cells were divided into four groups： control group， aspirin group （5 mmol／L）， trastuzumab group （30 μg／ml） and combination group （5 mmol／L aspirin+30 μg／ml trastuzumab）. MTT assay and flow cytometry were used to observe the effects of different drug treatment on cell proliferation and apoptosis. 
ResultsMTT assays showed that the relative proliferation rate of SKBR3 cells was （79.6±2.61）％ in aspirin group， （48.2±3.35）％ in trastuzumab group and （21.5±166）％ in combination group. Compared with aspirin group or trastuzumab group， the cell proliferation of combination group was significantly inhibited （P＜0.05）. Two drugs combined effect index was 10 of a superimposition effect. The apoptosis assays showed that the relative apoptotic rate of cells was （27.3±3.47）％ in aspirin group， （35.3±2.80）％ in trastuzumab group and （56.2±3.95）％ in combination group. Compared with aspirin group or trastuzumab group， the cell apoptosis of combination group was significantly increased （P＜0.05）. ConclusionAspirin combined with trastuzumab can effectively inhibit the growth of HER-2positive breast cancer cells， which may be a new model for the clinical treatment of HER-2positive breast cancer.

Key words: Breast cancer, Epidermal growth factor receptor2（HER-2）, Aspirin, Trastuzumab, Proliferation, Apoptosis