DRD4 and nonpapillary renal cell carcinoma: Through a LASSO regression with 1000-folds cross-validation to identify the optimal lambda value that came from the minimum partial likelihood deviance, we got 8 candidate FRGs (CD44, BID, DRD4, TRIB3, CDKN2A, SLC7A11, TAZ and MIOX) that were significantly associated with the prognosis of ccRCC (Figures 3B, C).