The XRCC1 Arg280His polymorphism enhanced susceptibility of DTC in Caucasians but protect against DTC in Asians (21, 23), whereas a homozygous XRCC1 Arg194Trp polymorphic genotype may increase the risk of PTC and lymphatic metastasis (19, 20, 24, 25). This evidence concerns the gene XRCC1 and Lymphatic Metastasis.