Serum PTX3 levels could significantly differentiate HCC from chronic hepatitis [AUC (95% CI) 0.943 (0.908–0.968), sensitivity 85.1%, specificity 89.3%, Fig. 1A], cirrhosis [AUC (95% CI) 0.907 (0.859–0.943), sensitivity 68.2%, specificity 99.0%, Fig. 2B] or chronic HBV infection without HCC [AUC (95% CI) 0.929 (0.898–0.953), sensitivity 79.4%, specificity 89.9%, Fig. 2C, Table 3). The gene discussed is PTX3; the disease is hepatocellular carcinoma.