SUFU and nonpapillary renal cell carcinoma: We found that the protein levels of SUFU detected in ccRCC cell lines, such as A498, 786-O, Caki-1, and Caki-2 were much less than in the normal kidney proximal tubular cell line HK2, while SPOP was highly expressed in A498 and 786-O cells, indicating that SUFU and SPOP were negatively correlated in ccRCC (Fig. 5A).