XRCC3 and cancer: Among the different DNA repair genes of the HRR, the X-ray repair complementing defective repair in Chinese hamster cells 3 (XRCC3) has been the subject of considerable investigation. XRCC2 and XRCC3 genes are structurally and functionally related to RAD51 which plays an important role in homologous recombination, a process, if defective, frequently involved in cancer transformation [7].