STAT1 and neoplasm: Notably, while this study does not directly establish that IFN-γ exerts its regulatory effects on HHLA2 expression via a STAT1-mediated mechanism, the existing research addressing the interplay between IFN-γ and IRF-1 provides us a compelling foundation for hypothesizing the involvement of the IFN-γ/JAK/STAT1/IRF-1/HHLA2 pathway in the promotion of tumor progression through the facilitation of immune escape in liver cancer.