RESUMEN
Objective To study the association between DNA double-strand break repair gene NBS1(nijmegen breakage syndrome gene)polymorphisms and the susceptibility to lung cancer.Methods A case-control study design was applied.PCR-RFLP was used to identify NBS1 polymorphisms among 575 lung cancer cases and 575 controls.Results The frequencies of C/C,C/G and G/G genotypes at NBS1 rs 1805794 site were 25.9%,51.8%,22.3% among controls compared to 20.5%,52.3%,27.1% among cases.There was significant difference between controls and cases(χ~2=6.38,P=0.04).Individuals carrying C/G + G/G genotypes had an increased risk for lung cancer (OR=1.46,95%CI:1.09-1.97)compared to the C/C genotype.The frequencies of G/G,G/C and C/C genotypes at NBS1 rs2735383 site were 37.9%,47.0%,15.1% among controls compared to 35.5%,48.5%,16.0% among cases,with no significant difference between the two groups(χ~2=0.75,P=0.69).Individuals earning Hap4-GC haplotype(OR=1.70,95%CI:1.24-2.31)and Hap4/Hap2 dihaplotype(OR=1.75,95%CI:1.11-2.76)had an increased risk on lung cancer.Joint associations of smoking and the NBS1 polymorphism with the risk of lung cancer were observed(P＜0.05).Conclusion The G/G genotype at NBS1 rs1805794 site and the Hap4-GC haplotype and Hap4/Hap2 dihaplotype from rs1805794 and rs2735383 were both associated with lung cancer.