Since the identification of XRCC3 Thr241Met polymorphism, a growing number of studies suggested that XRCC3 Thr241Met polymorphism plays an important role in the development of cancers, such as glioma [22], hepatocellular carcinoma [23], head and neck cancer [24], lung cancer [25], and so on. This evidence concerns the gene XRCC3 and lung cancer.