However, eleven genes (CRABP2, DDAH1, TGFA, SPATA18, SCGN, CYP39A1, IL15RA, APOLD1, NTN4, PABPC1L, and SIM2) have not been studied in relation to ccRCC, according to PubMed searches for “GENE and ccRCC”. This evidence concerns the gene NTN4 and nonpapillary renal cell carcinoma.