SULF2 and hepatocellular carcinoma: As shown in Figure 1A, TCGA database analysis revealed that the mRNA expression level of SULF2 in the HCC tissues was significantly and positively correlated with that of ACTA2 (actin alpha 2, smooth muscle; r = 0.512; P < 0.01), FAP (fibroblast activation protein; r = 0.654; P < 0.01), and POSTN (periostin; r = 0.512; P < 0.01), which are considered as CAF biomarkers (Figure 1A).