Cell-free circulating DNA: Diagnostic value in patients with renal cell cancer.

Objectives: To analyse the diagnostic and prognostic value of cell-free DNA in patients with renal cell carcinoma (RCC).

Patients And Methods: Cell-free DNA was measured in 35 patients with RCC and 54 healthy individuals using quantitative real-time PCR. ACTB-106 detects fragmented cell-free DNA due to apoptosis and ACTB-384 detects long DNA fragments by necrosis. DNA-Integrity (ACTB-384/ACTB-106 ratio) served as measure of DNA fragmentation.

Results: Levels of both DNA fragments were increased in RCC patients compared to healthy individuals (ACTB-384: 1.77 vs. 0.61ng/ml, p=0.0003; ACTB-106: 1.31ng/ml vs. 0.77 ng/ml p=0.003). Receiver operator characteristic analysis (ROC) showed at a threshold level of 1.03 ng/ml for ACTB-106 68.6%, sensitivity and 70.4% specificity (AUC: 0.69). ROC analysis showed at a threshold level of 1.70 ng/ml for ACTB-384 57.1%, sensitivity and 81.5% specificity (AUC: 0.73). DNA integrity was increased in RCC (1.07 vs. 0.72 p=0.04). In vascular invasion the DNA integrity was reduced (p=0.003).

Conclusion: Cell-free-DNA levels are increased in RCC. The DNA integrity indicates mostly necrotic origin in RCC.