A preliminary study of plasma cyclase-associated protein 2 as a novel biomarker for early stage and alpha-fetoprotein negative hepatocellular carcinoma patients

Background and objective: Cyclase-associated protein 2 (CAP2) has recently been suggested to be a candidate biomarker for hepatocellular carcinoma (HCC). We aim to investigate the application of CAP2 as a novel biomarker for HCC patients especially for those at early stage and are AFP-negative. Methods: The CAP2 and AFP plasma levels were analyzed by enzyme-linked-immunosorbent assay in 86HCC, 59cirrhotic patients, and 30normal individuals. Their correlation with HCC tumor behavior, disease stages, diagnostic sensitivity, specificity and accuracy were analyzed. Results: The results showed that both CAP2 and AFP plasma levels in HCC patients were significantly elevated when compared to cirrhosis and controls. CAP2 levels correlate well with HCC patient's histological grade, clinical stage and tumor size, but not with patient's age, gender, hepatitis B virus infection status and plasma AFP level. CAP2 had better sensitivity as compared to AFP (82.6% vs 59.3%) for general HCC, and early stage of HCC patients (78.6% vs 40.4%). In addition, CAP2 is able to complement AFP to predict 82.9% of HCC in AFP-negative patients. Conclusion: We suggest that CAP2 is a novel biomarker for HCC patient, this may be especially useful for detection of early stage HCC and when plasma AFP level is negative.