DBC1 (deleted in bladder cancer 1), also known as DBCCR1 or FAM5A, is a novel 761 amino acid cytoplasmic protein that functions as an essential regulator of tumorigenesis and mediates expression of components of the plasminogen pathway. Evolutionarily conserved and highly expressed in brain, DBC1 is found at weak levels in small intestine, lung, kidney, testis, prostate, thymus, heart and kidney. DBC1 contains one MACPF domain, belongs to the FAM5 family and inhibits cell proliferation at the G1S transition via negative regulation. DBC1 contains a 5' CpG island that, when hypermethylated, leads to silencing in 50 percent of bladder cancer cell lines.