The DNA repair gene X-ray cross-complementing group 4 (XRCC4), a member of the non-homologous end-joining (NHEJ) repair system, plays a major role in the repair of the double-strand breaks of the DNA sequence. This gene is critical to the maintenance of overall genome stability, and is also thought to play a key role in human carcinogenesis. In this case-control study, several novel polymorphic...