C4A and hepatocellular carcinoma: However the best predictive ability was found with the combination of C4a, FGA, CP and PON1 through the following formula:C4a×FGA×CPPON1The area under ROC curve of this combination to identify patients with HCC was 0.81, which was higher than the area under ROC curve of C4a and FGA separately (Fig. 3B).