XRCC1 and head and neck squamous cell carcinoma: However, some studies indicated that the XRCC1 Arg399Gln polymorphism do not confer a significant risk for HNSCC (Gal et al., 2005; Wu et al., 2014) and revealed that low expression of XRCC1 statistically significant increase the risk of HNSCC (Kumar et al., 2012).