AFP and hepatocellular carcinoma: The sensitivity and specificity of other RNA biomarkers (DANCR, HULC, miR-223, miR-21 and UCA1) (Fig. 8d) and classical protein biomarkers (AFP, DCP and AFP-L3) (Supplementary Figure 2B) for predicting HCC were lower than those of circ_104075, which suggests that circ_104075 is a promising serum biomarker for the diagnosis of HCC.