In all MDR cancer cell lines tested, incubation of KSQ‐4279 had few effects on ABCB1/ABCG2/ABCC1 expression both in mRNA level (Figure 5A) and protein level (Figure 5B,C), even given the treated concentration of KSQ‐4279 higher to 50 μM or the incubated time longer to 72 h. Here, ABCG2 is linked to cancer.