XRCC1 is a DNA repair protein.involved in the efficient repair of DNA single-strand breaks formed by exposure to ionizing radiation and alkylating agents. This protein interacts with DNA ligase III, polymerase beta and poly (ADP-ribose) polymerase to participate in the base excision repair pathway. It may play a role in DNA processing during meiogenesis and recombination in germ cells. A rare microsatellite polymorphism in this gene is associated with cancer in patients of varying radiosensitivity.Inhibition of XRCC1 phosphorylation by mutation of the CK2 phosphorylation sites or by preventing CK2 activity using a highly specific inhibitor ablated the rapid repair of cellular DNA single-strand breaks by XRCC1. These data identified a direct role for CK2 in the repair of chromosome DNA strand breaks and in maintaining genetic integrity.