XRCC1 and cancer: The potential role of these polymorphisms in cancer development lies in the fact that these polymorphic gene variations alter the level of DNA repair proteins and also act as biomarker for chemotherapeutic response.(Chen et al., 2016; Peng et al., 2014) The XRCC1 and APE-1 DNA repair genes was selected for this case control study because of their important role in maintaining genomic integrity.