Association between XPD (Lys751G1n) Polymorphism and Lung Cancer Risk: A Population-Based Study in Iran

Objective: people are usually susceptible to carcinogenic aromatic amines, presentin cigarrette smoke and polluted environment, which can cause dna damage. therefore,maintenance of genomic dna integrity is a direct result of proper function of dnarepair enzymes. polymorphic diversity could affect the function of repair enzymes andthus augment the risk of different cancers. xeroderma pigmentosum group d (xpd)gene encodes one of the most prominent repair enzymes and the polymorphisms ofthis gene are thought to be of importance in lung cancer risk. this gene encodes thehelicase, which is a component of transcription factor iih and an important part ofthe nucleotide excision repair system. studies reveal that individuals with lys751glnpolymorphism of xpd gene have a low repairing capacity to delete the damages ofultraviolet light among other xpd polymorphisms.materials and methods: in this case-control study, first lys751gln polymorphism wasgenotyped, then its association with lung cancer risk was analyzed. genomic dna wasextracted from the whole blood sample of 640 individuals from iran (352 healthy individualsand 288 patients). allele frequencies and heterozygosity of lys751gln polymorphismwere determined using polymerase chain reaction-restriction fragment length polymorphismmethod.results: according to statistical analyses, lung cancer risk in individuals with lys751glnpolymorphism (odd ratio=1.8, 95% confidence interval 0.848-3.819) is approximatelytwice as high as that of lys/lys genotype, however 751gln/gln genotype did not relate tolung cancer risk (odd ratio=0.7, 95% confidence interval 0/307-1/595).conclusion: this study suggests that heterozygous polymorphism (lys/gln) increasesthe sensitivity of lung cancer risk, while homozygous polymorphism (lys/lys) probablydecreases its risk and c allele frequency shows no remarkable increase in the patients.