Fanconi Anemia (FANC) is a human autosomal-recessive cancer susceptibility disorder characterized by congenital defects, progressive bone marrow failure, and cellular hypersensitivity to mitomycin C (MMC). The FANC subunit D2 protein is vital for cellular resistance to DNA cross-linking and the arrest of DNA synthesis after ionizing radiation. DNA damage activates the monoubiquitination of FANC D2, targeting nuclear foci containing the BRCA 1 protein.