ABCB1 and colonic neoplasm: Among the above, multidrug resistance mediated by P-gp, also known as multidrug-resistant protein 1 (MDR1) encoded by ABC subfamily member 1 (ABCB1), is the most common in clinical therapy of liver, kidney, and colon cancer, which endows cancer cells an ability to excrete exogenous chemotherapeutic drugs (i.e., doxorubicin) [16].