To elucidate the molecular mechanisms underlying the established drug‐resistant cancer cell models (Du145TXR resistant to taxol; MCF‐7ADR resistant to adriamycin) (Appendix Fig S1A and B), we first examined the expression of MDR1 (also known as p‐glycoprotein), which has been extensively studied in the context of drug‐resistant phenotype (Gouaze et al,2005; Takeda et al,2007; Robey et al,2018) and confirmed the marked upregulation of its protein expression (Appendix Fig S1C). Here, ABCB1 is linked to cancer.