Alteration of CYP4A11 expression in renal cell carcinoma: diagnostic and prognostic implications

Background: Cytochrome P-450 4A11 (CYP4A11) and peroxisome proliferator-activated receptor-α (PPARα) are expressed at high levels in renal proximal tubules, and upregulation of CYP4A11 protein levels is known to be influenced by PPAR agonists. The goal of this study was to evaluate the clinicopathological role of CYP4A11 expression in renal cell carcinoma (RCC). Methods: We performed immunohistochemical analysis of CYP4A11, CYP4A22 and PPARα and correlated the results with the clinicopathological features of RCC (n=139). Reverse transcription digital droplet polymerase chain reaction (RT-ddPCR) against CYP4A11 and CYP4A22 was also performed. Results: CYP4A11 mRNA expression levels were higher in non-neoplastic kidney tissues than in matched tumor tissues in 12 matched pairs of freshly frozen primary clear-cell RCC (ccRCC) and nontumor tissue (p=0.002). Immunohistochemical staining showed that CYP4A11 expression was significantly lower in ccRCC than in non-ccRCCs, including papillary, chromophobe, and unclassified RCCs (p<0.001). CYP4A11 expression was associated with PPARα expression, males and high nuclear histologic grades (p=0.001, p=0.018 and p<0.001). Univariate and multivariate analyses revealed that CYP4A11 expression was correlated with short overall survival (p=0.007 and p=0.010). Conclusion: These findings suggest that CYP4A11 expression is a potential poor prognostic factor of RCC. The considerable decrease in CYP4A11 expression is a predictive diagnostic factor of ccRCC, and CYP4A11 metabolism in ccRCC might be different from that in non-ccRCCs.