CD274 and hepatocellular carcinoma: MIAT and PD-L1 are upregulated in HCC. MIAT promotes STAT3 by downregulating miR-411-5p, increasing PD-L1 transcription. MIAT knockdown enhances T cell cytotoxicity, and miR-411-5p inhibition reverses STAT3 and PD-L1 suppression.