In the case of RCC, methylation analysis of serum cfDNA using GSTP1 alone or in combination with either APC, p14ARF, p16, RARB, RASSF1, TIMP3, or PTGS2 has been shown to provide a high accuracy of detection (AUC ranging from 0.73 to 0.75; 95% IC 0.50–0.84) [99]. This evidence concerns the gene APC and renal cell carcinoma.