CD274 and hepatocellular carcinoma: Utilizing the tumor tissues from 98 patients with HCC (Supplementary Table 1) to show the expression of PD-L1 and SALL4 in the peritumor and center tumor regions by immunostaining (Fig. 1b), we found that the expression of both SALL4 and PD-L1 was significantly increased in the center tumor regions (P < 0.0001, two-tailed unpaired Student’s t-test) (Fig. 1c, d).