IRF1 and hepatocellular carcinoma: However, Wang, R. et al. found that gamma interferons can upregulate IRF1 expression in HCC cells, which in turn activates human endogenous retrovirus-H long terminal repeat-associating 2 (HHLA2) expression and promotes M2 polarization and macrophage chemotaxis, potentially facilitating immune evasion and HCC progression [30].