PTGER1 and nonpapillary renal cell carcinoma: Based on the results of the LASSO analysis, we established a prediction model for ccRCC patients using the expression levels of the genes as follows: Risk score = (−0.113150947 * NPR3) + (0.046765504 * MDK) + (0.024601593 * IFNE) + (0.039980648 * NTF4) + (0.011819219 * PTGER1) + (0.036773937 * GAL) + (0.020128759 * FGF23) + (0.006482745 * CXCL13).