We further validated the expression of 4 genes in the set of pre-treated RCC tissues at the mRNA level, and the expression of QPCT and IRS1, but not SKI and PTK2B, was significantly higher in the sunitinib-nonresponsive group than in the responsive group (Figure 1E, Supplementary Figure 1C, Supplementary Table 3). Here, PTK2B is linked to renal cell carcinoma.