title: The -765C allele of the cyclooxygenase-2 gene as a potential risk factor of colorectal cancer: a meta-analysis.
abstract: Colorectal cancer (CRC) is the third leading cause of cancer-related death in the world. Human colorectal carcinogenesis is a complex, multistep and multigenetic process. Cyclooxygenase-2 (COX2), a key enzyme in arachidonic acid metabolism, is overexpressed in several epithelial malignancies including colorectal cancer. COX2 expression can be induced by pro-inflammatory and mitogenic stimuli. The -765G/C polymorphism of the COX2 gene promoter has been reported to affect CRC susceptibility, but recent studies have demonstrated conflicting results. To shed light on these inconclusive findings, we performed a meta-analysis for assessing the involvement of COX2 -765G/C polymorphisms at the onset of colorectal carcinoma. Literature-based searching was guided to gather data and either fixed-effect or random-effect model was used to pool the odds ratio (OR) according to the test of heterogeneity. The 10 eligible case-control studies included 3,322 colorectal cancer cases and 5,166 controls. Overall, no evidence has indicated that individuals carrying GC+CC genotypes had significantly increased colorectal cancer risk compared with GG genotype [OR = 1.06, 95% confidence interval (95% CI) = 0.94-1.20]. However, stratified analysis with ethnicity indicated that individuals carrying GC+CC genotypes had an increased risk of colorectal cancer (OR = 1.40, 95% CI = 1.11-1.76) among Asian population. In conclusion, although not all bias could be eliminated, the -765C allele of the COX2 gene may be a potential risk factor for colorectal cancer in Asians.
authors.affiliation: Department of Radiation Medicine, Chongqing Medical University.
authors.forename: Hui
authors.initials: H
authors.lastname: Cao
authors.forename: Zhong
authors.initials: Z
authors.lastname: Xu
authors.forename: Hao
authors.initials: H
authors.lastname: Long
authors.forename: Xiao-qing
authors.initials: XQ
authors.lastname: Li
authors.forename: Shao-lin
authors.initials: SL
authors.lastname: Li
mesh_terms: D000483:Alleles; D015179:Colorectal Neoplasms / Q000235:genetics*; D051546:Cyclooxygenase 2 / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D011110:Polymorphism, Genetic; D012307:Risk Factors
chemical_list: D051546:Cyclooxygenase 2