Single Nucleotide Polymorphisms Of CYP2D6 Gene G4268C,C188T And ERCC1 Gene C8092A And Their Genetic Susceptibility To Lung Cancer

IntroductionThe mechanism of genetic susceptibility to lung cancer in the significance of lung cancer has drawn increasing attention. Some studies have shown that some of the genetic polymorphism of metabolic enzymes is closely related to the occurrence lung cancer. Cytochromes P450 2D6 (cytochromes P450 2D6, CYP2D6) is an important liver phase I metabolizing enzyme. The tobacco-specific precarcinogen in the body through the CYP2D6 metabolic activation to become carcinogenic end to form DNA adducts, resulting in cell damage may involve changing the process of lung cancer caused by smoking. Racial differences are significant among CYP2D6 phenotypes and genotypes. One of Asians common single nucleotide polymorphism in exon 9 G4268→C transversion, resulting in Ser486→Thr amino acid replacement, leading to decreased expression of enzyme activity, and the other one Asians common single nucleotide polymorphism, is CYP2D6 exon 1 C188→T transition, resulting in Pro34→Ser amino acid replacement, leading to unstable enzymes encoded to reduce the activity of CYP2D6 to reduce pre-carcinogen metabolism may affect individual susceptibility to lung cancer. Nucleotide excision repair system(nucleotide excision repair, NER) is composed of many repair genes, among which ERCC1 (excision repair cross-complementing 1,ERCC1)located on human chromosome 19q13.2-19q13.3, size 33kb, contains 17 exons ERCC1 purified protein and 633 amino acid, is a symbol gene of NER activity and is necessary DNA repair gene for cell survival, and its encoded products is 297 amino acids. The relationship between its polymorphism and lung cancer susceptibility is not too much, so this is also a valuable research direction. In this study, case-control methods is used to explore the effect of CYP2D6gene G4268C and C188T and ERCC1 C8092A single nucleotide polymorphism on lung cancer risks in Liaoning Province.Materials and Methods一,Materials(一) ObjectIn this case-control study, lung cancer patients and normal controls of 200 cases respectly. Specimens from the First Affiliated Hospital of China Medical University from May to December in 2009.Both of the primary lung cancer patients confirmed by pathology examination and normal individuals are in Liaoning Han areas.(二) Equipments and reagentsPCR device, Bio-Rad. KI, chloroform, isoamyl alcohol, isopropyl alcohol, ethanol, PCR Kit purchased from TAKARA company.二,Methods(一) KI method for rapid extraction of genomic DNA from human peripheral blood.(二) PCR reactionsDesign primers sequence; configure system to carry out PCR reaction.(三) RFLP digestion reaction:Adding PCR product obtained by the above-mentioned to restriction endonuclease,37-degree water bath. Staining analysis after digestion products obtained using 2.5% agarose gel electrophoresis.(四) Date and statistical analysisWith SPSS11.5 software, data was tested by Hardy-Weinberg equilibrium.x2 test is used to analyze CYP2D6 or ERCC1 gene polymorphism and lung cancer relationship. The relative strength of the relationship was shown by odds ratio (OR) and 95% confidence interval (CI).Carrying out non-conditional Logistic analysis, testing standard isα= 0.05.Results一,Basic information on subjects.In this study a total of 132 male and 68 female patients with lung cancer,, average age 54 (24-82) years. In control group,135 men and 65 women, average age 55 years (27-80) years. Gender composition and the average age of the two groups ware no significant difference (P>0.05). Smoking more than one day, continued for more than six months, defined as smokers, the cumulative amount of smoking (amount·year)= the number of cigarettes smoked per day×smoking years. According to WHO (1984) smoking survey methodology standards, boundaries of light and heavy degrees of smoking to smokers in control group the median cumulative cigarette consumption 400·year standard, the cumulative amount of smoking≥400 cigarettes·years of smoking was severe, the cumulative amount of smoking 400 cigarettes·year was light smokers. The proportion of lung cancer smoking and the proportion of heavy smokers were higher (P<0.05). Comparing smokers and non-smokers, increased risk of lung cancer [OR= 3.16 (95% CI=1.97-5.06)].二,G4268C genotype and the risk of lung cancer(一)In control group allele frequencies were in Hardy-Weinberg equilibrium (x2 = 2.52, P>; 0.60), which were representative. G4268/G, G4268/C and C4268/C these three kinds of genotypes in lung cancer group and the control group the distribution of frequencies were 1.50%,58.00%,40.50% and 2.50%,44.00%,53.50%; in two groups 4268C gene frequencies were 69.50% and 76.50%, which is not statistically different. Non-C4268/C genotype of the individual risk of lung cancer C4268/C genotype of 1.73 times (95% CI=1.02-2.95), especially in adenocarcinoma OR= 2.75 (95% CI= 1.27-5.94)(二) In order to carry C/4268C genotype without smoking as a reference, C4268 /C genotype smokers, adjusted OR= 2.61 (95% CI= 1.02-4.84), non-C4268C genotype non-smokers, adjusted OR= 2.59 (95% CI= 1.24-4.69), non-C4268C the combined effects of genotype and smoking adjusted OR= 5.29 (95% CI= 2.31-8.57), higher than the level of the two separate roles. In the interaction analysis, interaction between the two does not have multiplied (x2= 0.26, P= 0.636).(三) In the light smokers in the C4268/C genotype adjusted OR= 0.29 (95% CI= 0.03-1.92), non-C4268/C of the OR value of 3.41 (95% CI= 1.24-9.93), and the of lung cancer has a strong correlation; heavy smokers have a strong association with lung cancer, heavy smokers among the crowd carrying C4268/C genotype of lung cancer risk adjusted OR= 6.36 (95% CI=2.48-19.51), to carry non-C4268/C genotype adjusted OR= 3.26 (1.48-7.87), did not find C4268/C genotype of the protective effect.三,C188T genotype and the risk of lung cancer(1) control group allele frequencies in Hardy-Weinberg equilibrium (x2= 3.75, P> 0.05), can be considered representative of the population. C188/C, C188/T, and T188/T these three kinds of genotypes in lung cancer group and the control group the distribution of frequencies of 21.00%.49.50%.29.50% and 18.50%.39.00%.42.50%; 188T allele frequency respectively 54.25% and 62.00%, allele frequency differences between the two groups no statistical significance. Non-T188/T genotype the risk of lung cancer is 1.78 times of the T188/T genotype (95% CI= 1.10-3.04), especially in squamous cell carcinoma OR= 2.57 (95% CI= 1.13-5.46).(2) To carry T188/T genotype without smokers as a reference, T188/T genotype smokers, adjusted OR= 3.21 (95% CI= 1.23-7.48), non-T188/T genotype non-smoking are adjusted OR= 2.19 (95% CI= 1.05-4.37), non-T188/T genotype and the combined effects of smoking adjusted OR= 3.84 (95% CI= 1.69-8.72), higher than the level of the two separate roles. In the interaction analysis, interaction between the two does not have multiplied (x2= 1.36, P= 0.292).(3) In the light smokers in the T188T genotype adjusted OR= 0.39 (95% CI= 0.06-1.92), non-T188T genotype adjusted OR= 3.41 (95% CI= 1.24-9.93), and has strong correlation lung cancer; heavy smokers have a strong association with lung cancer, too.四,C8092A genotype and the risk of lung cancerAllele frequency in the control group is in Hardy-Weinberg equilibrium (x2= 3.75, P>0.05), representative of the population. C8092/C, C8092/A and A8092/A genotype of these three kinds of lung cancer and control groups in the distribution of frequencies were 118.50%,38.00%,43.50% and 19.00%,39.50%,41.50%,respectively. In two groups 4268C gene frequencies were 62.50% and 61.25% Allele frequency difference was not statistically significant. Non-A8092/A genotype the risk of lung cancer is the A8092/A genotype of 0.98 times (95% CI= 0.59-2.04).ConclusionThe relationship between CYP2D6 polymorphism and lung cancer susceptibility research results is often contradictory. Some studies shows CYP2D6 polymorphism and risk of lung cancer associated With increased activity of CYP2D6, tobacco's role in lung cancer risk has also increased, and this with the kinds of effects of tobacco consumption increases, thus confirming the CYP2D6 activity can be modified tobacco on the role of risk of lung cancer, but some researches have also denied the existence of such a correlation.The results suggest that, CYP2D6 nonC4268/C and none T188/T genotypes were associated with lung cancer moderately, and nonC4268/C genotype to an increased risk of adenocarcinoma. Lung cancer is a multi-factor multi-stage chronic disease, which is caused by the interaction of environmental exposure and individual genetic factors. In the course of lung cancer, smoking and exposure to factors such as risk factors for lung cancer arising from the main effects of individual G4268C and C188T mutation may cover the impact of lung cancer susceptibility. NonC4268/C and nonT188/T genotypes and the combined effects of smoking is higher than the role of the two separate one. However, in the course of the occurrence of lung cancer, they do not have the synergy between smoking and non-mutant Although the relationship between ERCC1 C8092A and platinum-based chemotherapy sensitivity in research are beginning to come out, but this study did not find that the polymorphism associated with susceptibility to lung cancer. Concrete joint between the mode of action and mechanisms need further study.