Fig 2: Representative photographs of CYP4A11 and PPARa immunohistochemical staining of the normal kidney cortex, clear-cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma. The normal renal tubular epithelial cells (A and D) and papillary renal cell carcinoma cells (C and F) show strong positive cytoplasmic staining for CYP4A11 (*) and positive nuclear staining for PPARa (^), in contrast to the ccRCC cells (B and E), which exhibit weak staining (scale bar = 20 µm).

Fig 3: Droplet digital PCR amplification plots for individual cases. Comparison of CYP4A11 and CYP4A22 mRNA expression levels by reverse transcriptase digital droplet PCR (RT-ddPCR) in 12 paired clear-cell renal cell carcinoma and nontumor tissue samples. Positive droplets are shown in blue, and negative droplets are shown in black/gray. The pink line represents the threshold, dichotomizing positive and negative droplets. (p = 0.002 and p = 0.012, Wilcoxon signed-rank test).

Fig 4: Kaplan-Meier overall survival curves for CYP4A11 protein expression levels in renal cell carcinoma. (A) High CYP4A11 expression was associated with short overall survival (p=0.005; log-rank test). (B) The CYP4A11 expression levels did not show statistical significance in terms of the disease-free survival outcome (p=0.945; log-rank test). (C) The CYP4A11 mRNA expression levels are marginally significant prognostic factors for overall survival in GSE2748 (p=0.08; log-rank test).