ROC Curve Analysis: Area under ROC curve at 95% CI for CK18 by extended trapezoidal rule = 0.998333 with Optimum cut-off point selected = 534.5 while for AFP it was = 0.966667 with Optimum cut-off point selected= 134 for HCC diagnosis (Fig. 4). The gene discussed is KRT18; the disease is hepatocellular carcinoma.