PBDEs are widely used in consumer and household products as flame retardants. Many studies have shown that PBDEs could disrupt thyroid hormone homeostasis and adversely affect brain development. Here, we explored the toxical effects of BDE209 on HEK 293 cells and found that BDE209 may have a role in nucleosome remodeling. Many gene sets involved in cancer are enriched at the BDE209-treated sample. This indicates the carcinogenicity of BDE209. Interestingly, the impacts of BDE209 dissoved in DMSO on gene expression are more pronounced than the simple additive effects of BDE209 and DMSO alone. Overall design: Gene expression profiles of human embryonic kidney 293 cells (HEK 293) cultured in normal medium, and medium containing BDE209 or DMSO were generated by deep sequencing, using Illumina HighSeq2000, respectively..