SMAD4 and malignant colon neoplasm: The sensitivity of LoVo colon cancer cells to chemotherapeutic drugs and P-gp and SMAD4 expression [19] were detected before and after the knockdown of OLR1. In the experiment of cell drug resistance, the conventional treatment drugs such as DDP, oxaliplatin, 5-Fu, and paclitaxel were selected for the study [16].