PIF1 and nonpapillary renal cell carcinoma: Figure 2B shows that the mRNA expression levels of PIF1 in ccRCC tissues (n = 72) were significantly higher than those in adjacent normal tissues (n = 72) (Figure 2B, 0.559 ± 0.297 vs. 0.213 ± 0.239, Mann‒Whitney U test, p < 0.001). The results of immunohistochemistry staining of HPA showed that PIF1 protein expression was also upregulated in ccRCC tissue, as shown in Figures 2C,D.