SETBP1 (SET binding protein 1), also known as SEB, is a 1,542 amino acid nuclear protein that contains three AT hook DNA-binding domains, one SKI homology region and a C-terminal SET-binding domain, which is followed by three PPLPPPPP repeats. SETBP1 may be involved in SET-related tumorigenesis and leukemogenesis by regulating the transforming activity of SKI in the nucleus or suppressing SET function. As a widely expressed protein, SETBP1 is encoded by a gene that maps to human chromosome 18, which houses over 300 protein-coding genes and contains nearly 76 million bases. There are a variety of diseases associated with defects in chromosome 18-localized genes, some of which include Trisomy 18 (also known as Edwards syndrome), Niemann-Pick disease, hereditary hemorrhagic telangiectasia, erythropoietic protoporphyria and follicular lymphomas.