Since both TOPK and MELK were overexpressed in kidney cancer [26, 27], we examined the half-maximum inhibitory concentration (IC50) value to measure the growth inhibitory effect of OTS514 and OTS167 on five kidney cancer cell lines, VMRC-RCW, Caki-1, Caki-2, 769-P and 786-O, in which TOPK and MELK were highly co-expressed (Figure 4A-4E). Here, PBK is linked to kidney cancer.