In addition, it has been reported that insulin can directly up-regulate hepcidin expression in hepatocellular carcinoma (HepG2) cells by enhancing signal transducers and activators of transcription 3 (STAT3) protein synthesis and DNA binding activity [16], indicating that insulin disorder in T2DM can lead to inadequate hepcidin concentrations. This evidence concerns the gene HAMP and type 2 diabetes mellitus.