Tumor-associated autoantibodies are useful biomarkers in immunodiagnosis of á-fetoprotein-negative hepatocellular carcinoma

AIM To determine the prevalence and diagnostic value of autoantibodies in á-fetoprotein (AFP)-negative hepatocellular carcinoma (HCC). METHODS Fifty-six serum samples from AFP-negative HCC cases, 86 from AFP-positive HCC cases, 168 from chronic liver disease cases, and 59 from normal human controls were included in this study. Autoantibodies to nucleophosmin (NPM)1, 14-3-3zeta and mouse double minute 2 homolog (MDM2) proteins in AFPnegative HCC serum were evaluated by enzymelinked immunosorbent assay. Partially positive sera were further evaluated by western blotting. Immunohistochemistry was used to detect the expression of three tumor-associated antigens (TAAs) in AFP-negative HCC and normal control tissues. RESULTS The frequency of autoantibodies to the three TAAs in AFP-negative HCC sera was 21.4%, 19.6% and 19.6%, which was significantly higher than in the chronic liver disease cases and normal human controls (P < 0.01) as well as AFP-positive HCC cases. The sensitivity of the three autoantibodies for diagnosis of AFP-negative HCC ranged from 19.6% to 21.4%, and the specificity was approximately 95%. When the three autoantibodies were combined, the sensitivity reached 30.4% and the specificity reached 91.6%. CONCLUSION Autoantibodies to NPM1, 14-3-3zeta and MDM2 may be useful biomarkers for immunodiagnosis of AFP-negative HCC.