SLC44A4 and nonpapillary renal cell carcinoma: As shown in Figure 5, the expression levels of SLC22A6, SLC22A7, SLC22A13, SLC25A4, SLC34A1, and SLC44A4 in ccRCC were significantly correlated with the OS and DFS of patients, and the difference was statistically significant (P < 0.01).