DNA Methylation analysis of polybrominated diphenyl ethers (PBDEs) treated hepatocellular carcinoma

DE-71, a commercial mixture of the polybrominated diphenyl ethers (PBDEs), is used as flame retardant and the potential exposure to PBDEs is an emerging public health concern. It has been clarified that long term exposure to PBDEs induces hepatocellular carcinoma in mouse. In this study, we analyzed how DE-71 impacts on DNA methylation in hepatocellular carcinoma. DE-71 (technical pentabromodiphenyl oxide; CAS. No. 32534-81-9) was obtained from Great Lakes Chemical Corporation (West Lafayette, IN - Lot 2550OA30A). The chemical was administered to male B6C3F1/N mice (Taconic Farms, Inc. (Germantown, NY) by oral gavage in corn oil 5 days per week at doses of 100 mg/kg/day for up to 18 months. Frozen liver tissue/tumors were collected for DNA extraction at necropsy of control and high dose mice at 18 months. Methylated CpG Island Recovery Assay (MIRA) was used.