Previous studies show that tetrandrine could reverse MDR mediated by ABCB1 transporter in acquired resistant cancer cells such as MCF-7/Adriamycin [19], KBv200/vincristine [20], HCT15 (ABCB1 positive) [21] , multidrug resistance T lymphoblastoid leukemia cell line MoLT-4 [22], hepatocellular carcinoma Bel-7402/Adriamycin [23], mouse leukemia cell P388/Adriamycin [24], K562/doxorubicin [25], and T-cell acute lymphoblastic CEM/Adr5000 [26], osteosarcoma cell line U-2os [15], other multidrug resistant OS cell lines [27], and the human gastric carcinoma cell line SGC7901 [28]. Here, ABCB1 is linked to cancer.