review paper: association of transforming growth factor beta-1 -509c/t gene polymorphism with ischemic stroke: a meta analysis

introduction: transforming growth factor-beta 1 (tgf-β1) is a pleiotropic cytokine with potent anti-inflammatory property, which has been considered as an essential risk factor in the inflammatory process of ischemic stroke (is), by involving in the pathophysiological progression of hypertension, atherosclerosis, and lipid metabolisms. -509c/t tgf-β1 gene polymorphism has been found to be associated with the risk of is. the aim of this meta-analysis was to provide a relatively comprehensive account of the relation between -509c/t gene polymorphisms of tgf-β1 and susceptibility to is. methods: a review of literature for eligible genetic association studies published before october 20, 2014 was conducted in the pubmed, embase, google scholar and trip database. the strength of association was calculated by pooled odds ratios (ors) with 95% confidence intervals using revman 5.3 software. heterogeneity was examined using higgins i-squared, tau-squared, and chi-squared tests. results: a total of 2 studies involving 614 cases and 617 controls were found. the overall estimates did not show any significant relation between tgf-β1-509c/t polymorphism and risk of is under dominant (cc+ct vs. tt: or=1.01, 95%ci=0.31 to 3.26; p=0.99), recessive (cc vs. ct+tt: or=0.94, 95%ci=0.47 to 1.90; p=0.87), and allelic models (t vs. c: or=1.06, 95%ci=0.55 to 2.04; p=0.86). conclusion: this meta-analysis showed that tgf-β1-509c/t gene polymorphism no significant association with the susceptibility of is. further well-designed prospective studies with larger sample size are needed to confirm these findings.