To identify the most representative genes of the signature related to Stage AJCC, we performed a forward search feature selection Variable Ranking Based on Mutual Information Difference, resulting in a 13-gene signature (AR, AL353637.1, DPP6, FOXJ1, GNB3, HHLA2, IL4, LIMCH1, LINC01732, OTX1, SAA1, SEMA3G, ZIC2–Figure A3) able to predict distinct outcomes (high, moderate, and low survival risk) of patients with ccRCC. This evidence concerns the gene DPP6 and nonpapillary renal cell carcinoma.