The Relation between Polymorphisms in Exon 5 and Exon 6 of GSTP1 Gene and the Risk of Lung Cancer in Iranian People

摘要

Objective: The GSTP1 gene, which is located on chromosome 11q13, consists of 7 exons and 6 introns. Thereare two polymorphisms in GSTP1 that have been exposed to a transposition for codon 105 (Ile/Val) and 114 (Ala/Val)in exons 5 and 6, which have been studied previously in relation to lung cancer. Since the level of GSTP1 expressionin lung tissues and other human epithelial tissues is high, GSTP1Val-105 polymorphism is recognized as a sensitivefactor for tobacco-related cancers, especially lung cancer. Methods: One hundred and twenty tissue block samplesof patients with lung cancers and 120 peripheral blood samples of the control group were obtained from two referralcancer centers in Tehran, Iran, from 2011 to 2016. Genomic DNA was extracted from tissue blocks and buffy coat ofstudy cases to detect SNP of GSTP1 gene using Tetra-primer ARMS-PCR. Results: There was a notable correlationbetween the incidence of lung cancer and variant Val105 (P-value=0.001; OR=2/6; 95% CI=1.49-4.53) and Ile105(P-value=0.003; OR=0.41; 95% CI=0.23-0.73). The odds ratio for lung cancer in the homozygous Ile105/Ile105genotype was 3.56 times higher than that of individual with heterozygous Ile105/Val105 (P-value0.001; OR=3/56;95% CI=1.826-6.934) genotype, that was statistically significant. Furthermore, the results showed that there was nosignificant correlation between Ala114/Val114 genotypes and lung cancer. The BC (P-value=0.007; OR=0.16; 95%CI=0.04-0.61) and AA (P=0.001) genotypes were statistically significant (P-value 0.05); and for those who had AAgenotype, the odds ratio was almost six times higher than those with BC genotype. Conclusions: The study of GSTP1polymorphisms indicated that unlike the polymorphism in exon 5, the GSTP1 exon 6 polymorphism correlated withthe lung cancer risk in the select group of Iranian people. Likewise, the potential use of this genetic polymorphism asa lung cancer predictor is confirmed.