AFP and hepatocellular carcinoma: There was no significant difference between AFP and the PP value in differentiating HCC patients from NCs whether in the training dataset (z = 1.242, p = 0.214) or in the validation dataset (z = 0.268, p = 0.789), but the sensitivity in the early stage of HCC predicted by the PP value was higher than that predicted by AFP (p = 0.019), as shown in Figure S5.