By real-time quantitative PCR analysis a progressive increase in the KEAP1 transcript abundance was observed after 48 h (p < 0.0001) and was shown to correlate in ccRCC FW, ccRCC FG-2, ccRCC 5 with a decreased KEAP1 promoter methylation at 48 h (p < 0.001 respectively), (Figure 4B, 4D, 4F). This evidence concerns the gene KEAP1 and nonpapillary renal cell carcinoma.