Figure 1. Oxaliplatin resistance of SW480/R and HT29/R. (A) MTT assays were performed to evaluate the cytotoxicity of different concentrations of oxaliplatin (0~30 μM) to SW480, SW480/R, HT29 and HT29/R. *P<0.05. (B) IC50 of oxaliplatin to SW480, SW480/R, HT29 and HT29/R. *P<0.05.