PIK3R5 and nonpapillary renal cell carcinoma: Previously well-established cancer genes (including PIK3CG, PIK3R3 and PIK3R5, EGFR, CCND1 and TP53), as well as genes encoding key enzymes (ALDH1B1and ALDH2) were predicted to play essential roles in ccRCC development based on integrated pathway analysis.