STAT3 and hepatocellular carcinoma: In hepatocellular carcinoma, stabilization of HIF-1α is accompanied by stabilization of signal transducer and activator of transcription (STAT3); in human HepG2 liver cancer cells, melatonin and Stattic (a selective STAT3 inhibitor) showed a synergistic effect on STAT3, HIF-1α, and VEGF expression levels by impairing the binding of the STAT3, HIF-1α, and CBP/p300 transcriptional complex to the VEGF promoter, thus decreasing its transcriptional activation [45].