Compared with never-smokers carrying the wild-type genotype of LIG4 rs1805388, those ever-smokers with variant-containing genotype of LIG4 rs1805388 polymorphism had a significantly increased risk to develop gliomas (adjusted OR, 1.67; 95% CI, 1.11-2.50) (Table 4). This evidence concerns the gene LIG4 and central nervous system cancer.