HCC exosomal miR-23a-3p upregulates the programmed cell death ligand 1 (PD-L1) expression in macrophages via Signal transducer and activator of transcription 3 (STAT3) signaling, which significantly attenuates melatonin-treated HCC cell-derived exosomes (41). The gene discussed is STAT3; the disease is hepatocellular carcinoma.