CD274 and hepatocellular carcinoma: We found that the elevated proportions of PD-L1+ exosomes in HMGB1/RICTOR 3′UTR overexpressed HCC cells were downregulated after inhibition of mTORC1 (Supplementary Fig. 6c), which confirmed that HMGB1 and RICTOR mRNAs epigenetically promotes PD-L1 level in HCC cells via an mTORC1-dependent mechanism.