Relationship Between Polymorphisms Of DNA Repair Gene ERCC1, XRCC3 And Susceptibility To Lung Cancer

PartⅠRelationship between polymorphisms of DNA repair gene XRCC3 and susceptibility to lung cancerBackgroud and purpose: Some studies have demonstrated that polymorphisms of DNA of repair gene can impact the susceptibility to tumor. So the susceptible group can be chosen through different genetype of DNA repair gene and maybe get the early prevention, early diagnosis,early treatment.The aim of this study is to analyze the polymorphisms of DNA repair gene XRCC3 and relationship between genetic variations and susceptibility to lung cancer.Methods A case-control study of 291 patients with lung cancer and 273 cancer-free subjects as a control group was conducted from September 2006 to May 2007 to detect XRCC3 polymorphisms at loci. Genetypes of XRCC3 were analyzed by real time PCR using Taqman probes.Results Compared with never smoking subjects with wild homozygous genetype(Thr/Thr) , smokers with the same genetytpe (Thr/Thr) had increased risk of lung cancer , adjusted odds ratio (OR) 2.47 (95%CI:1.49～4.08 P<0.01). Smokers with heterozygous genetype(Thr/Met) also had increased risk of lung cancer, adjusted OR is 2.28(95%CI:1.21～6.60 P=0.02). XRCC3 codon 241 homozygous genetype (Thr/Thr) and pack-years of smoking less than 30 had a weak protective effect on adenocarcinoma (OR= 0.49,95%CI:0.26～0.93 P= 0.03). Allel Met of XRCC3 codon 241 and smoking might increase the risk of squamous cell carcinoma(OR =9.69, 95% CI :3.27～28.72 P< 0.01) ;furthermore, those with allel Met of XRCC3 codon 241 and pack-years of smoking less than 30 or more than 30 have different risk of squamous cell carcinoma,the OR were 8.00(95%CI:1.97～32.52, P<0.01), and 11.67(95%CI:2.98～45.73 , P<0.01) respectively.Conclusion The results demonstrated that genetic polymorphism of XRCC3 DNA repair gene may contribute to the susceptibility to lung cancer and have synergistic effect with smoking.PartⅡRelationship between polymorphisms of DNA repair gene ERCC1 and susceptibility to lung cancerBackgroud and purpose: The latest studies have demonstrated that polymorphisms of DNA of repair gene can impact the susceptibility to tumor. So the susceptible group can be chosen through different genetype of DNA repair gene and maybe get the early prevention, early diagnosis,early treatment.The aim of this study is to analyze the polymorphisms of DNA repair gene ERCC1 and relationship between genetic variations and susceptibility to lung cancer.Methods: A case-control group study of 291 patients with lung cancer and 273 cancer-free subjects as a control group was conducted to detect ERCC1 polymorphisms at loci. Genetypes of ERCC1were analyzed by real time PCR techniques using Taqman probes.Results: In never smoking people, a significant difference was found in the 3 genetype (C/C,C/T,T/T) between cases and controls(χ2=9.89,P=0.01). In nener smoking people, compared with homozygous genetype(C/C),ERCC1 codon 118 homozygous genetype(T/T) might increase the risk of lung cancer, the adjusted OR is 3.16(95%CI:1.29-7.73,P < 0.01 = .Compared with homozygous genetype(C/C) and never smoking ,those with smoking dose>25 pack-year and homozygous genetype(C/C) or heterozygous genetype (C/T) might increase the risk of lung cancer, the adjusted OR are 2.62(95%CI:1.54-4.44),2.41(95%CI:1.36-4.26,P<0.01=respectively. Compared with homozygous genetype(C/C), homozygous genetype(T/T) might increase the risk adenocarcinoma (OR=2.29, 95%CI: 1.05-4.78,P=0.03).Conclusion: The results demonstrated that genetic polymorphism of ERCC1 DNA repair gene might contribute the susceptibility to lung cancer and have synergistic effect with smoking.