PRCC and nonpapillary renal cell carcinoma: Based on candidate genes selected for subtype classification (Fig. 1), a final gene signature of 174 genes (the top 58 subtype-specific genes per ccRCC, pRCC, and chRCC) (Additional file 2: Fig. S3B; Additional file 6: Table S4) was developed using cohorts C1 and C2 as outlined in supplementary methods (Additional file 1: Supplementary methods; Additional file 2: Fig. S2/S3).