Cyclooxygenase 2 genetic variant interacting with tobacco smoking and the risk of lung cancer

Abstract

To explore the association of -1195G > A genetic variant in the promoter region of cyclooxygenase 2 genetic (COX2) with the genetic susceptibility of lung cancer and its interaction with smoking. Totally, 956 lung cancer patients recruited between January 2000 and December 2008 at Cancer Hospital, Chinese Academy of Medical Science as the case group, and 994 frequency-matched controls were randomly selected from a pool of cancer-free subjects recruited from a nutritional survey. All subjects were ethnic Han Chinese. There was no sex, age restrictions. Case group and control group were matched. Informed consent was obtained and 2 ml peripheral blood was collected from each subject. All samples were genotyped by polymerase chain reaction-restriction fragment length polymorphism method, smoking status of the subjects was surveyed.While the OR and 95% CI were estimated by logistic regression to evaluate the relation of COX2 -1195G > A variant and the risk of lung cancer. The genetic allele COX2 -1195AA of control group and case group were 24.9% (247/994) and 28.3% (271/956) . Case-control analysis showed an increased risk of developing lung cancer for -1195AA genotype carriers (OR = 1.36, 95% CI: 1.03-1.79), compared with -1195GG carriers. When stratified by smoking status, the significant increased risk of lung cancer was found among smokers with COX2-1195AA genotype, with the OR (95%CI) was 1.56 (1.08-2.25); while among non-smokers, difference of lung cancer risk was not found among different genotypes (OR = 1.17; 95%CI: 0.77-1.61). Among heavy smokers (pack-year >20), -1195AA and -1195AG genotype carriers have significant increased risk of lung cancer with 1.85 (1.16-2.95) and 1.62(1.08-2.43) of OR (95%CI), respectively; among light smokers (pack-year ≤ 20), the OR (95%CI) of lung cancer risk in -1195AG and -1195AA genotype carriers were 0.78 (0.47-1.30) and 1.08 (0.60-1.94), respectively. Genetic polymorphism in the promoter of COX2 gene interacting with smoking factor plays an important role in the development of lung cancer.