SIP1 is downregulated in hepatocellular carcinoma by promoter hypermethylation

Background: Smad interacting protein-1 is a transcription factor that is implicated in transforming growth factor-beta/bone morphogenetic protein signaling and a repressor of E-cadherin and human telomerase reverse transcriptase. It is also involved in epithelial-mesenchymal transition and tumorigenesis. However, genetic and epigenetic alterations of SIP1 have not been fully elucidated in cancers. In this study, we investigated mutations and promoter hypermethylation of the SIP1 gene in human hepatocellular carcinomas.