ABCB1 and cancer: At the same time, the overexpression of the ABC transporter is one of the causes of MDR in tumor cells leading to chemotherapy failure, and while the relationship between ABC expression level and KRAS mutation in cancer cells can be confirmed (Mohelnikova-Duchonova et al., 2013; Wei et al., 2016), the relationship between the expression level of ABC transporters and KRAS inhibitor is not clear, and the effect of ARS-1620 on ABCB1-mediated MDR has not been studied yet.