Elevated levels of circulating cell-free DNA in the blood of patients with hepatitis C virus-associated hepatocellular carcinoma.

BACKGROUND Circulating cell-free DNA is present in increased amounts in the blood of patients with one of several forms of cancer. MATERIALS AND METHODS A real-time PCR assay with glutathione S-transferase pi (GSTP1) gene was used to measure cell-free DNA levels in the sera of 52 patients with hepatocellular carcinoma (HCC) associated with hepatitis C virus (HCV), which included 30 HCV carriers without known HCC and 16 HCV-negative non-cancer patients (controls). RESULTS Cell-free DNA levels were significantly higher in the sera from HCC patients than in the sera from HCV carriers or the control subjects. Cell-free DNA levels were associated with the degree of tumor differentiation and size but not patient age, gender, TNM stage or levels of alpha-fetoprotein (AFP) or protein induced by vitamin K absence (PIVKA-II). The cell-free DNA assay had a sensitivity of 69.2% and a specificity of 93.3% in discriminating HCC and HCV carriers at the optimal cut-off value of 73.0 ng/ml, with an area of 0.90 (95% CI, 0.83-0.96) under the receiver operating characteristic curve. The discriminative power of cell-free DNA was superior to that of AFP or PIVKA-II. CONCLUSION Our results showed that levels of circulating cell-free DNA are significantly increased in sera of patients with HCV-associated HCC, suggesting that circulating cell-free DNA may be a good biomarker specific for HCV-associated HCC.