EP300 and hepatocellular carcinoma: Myocyte enhancer factor 2D (MEF2D) is a transcription factor that is overexpressed in HCC and is associated with poor survival of HCC patients.129 Researchers found that when HCC cells are exposed to interferon gamma (IFN-γ), p300 acetylates MEF2D and promotes its binding with the PD-L1 promoter, leading to increased PD-L1 expression.