CYP4A22 and nonpapillary renal cell carcinoma: RT-ddPCR analysis of CYP4A11 and CYP4A22 mRNA in 12 matched pairs of ccRCC tissue and non-neoplastic renal cortical tissue from 12 patients showed higher copy numbers of CYP4A11 and CYP4A22 in non-neoplastic tissue than in ccRCC tissue (p=0.002 and p=0.012, Wilcoxon signed-rank test).