Association between TGF-β1-509C/T polymorphism and endometriosis: a systematic review and meta-analysis

To evaluate the association between the transforming growth factor β1 gene-509C/T (TGF-β1-509C/T) polymorphism and the risk of endometriosis.

Relevant studies published before October 2011 were identified by searching PubMed and Embase. Studies were selected using prior defined criteria. The strength of the relationship between the TGF-β1-509C/T polymorphism and endometriosis risk was assessed by Odds Ratios (ORs). Fixed- or random-effects model was calculated according to study heterogeneity. Stratification analysis and sensitivity analysis were also conducted. Possible publication bias was tested by funnel plots and Egger's test.

Of 49 potentially relevant studies, six case-control studies were identified in this meta-analysis. The integrated result showed that the TGF-β1-509C/T polymorphism was not associated with the endometriosis risk for the allele contrast (T vs. C: OR=1.57, 95%CI=0.88-2.79), the additive genetic model (T/T vs. C/C: OR=2.96, 95%CI=0.97-9.10), the dominant genetic model (T/T+T/C vs. C/C: OR=1.80, 95%CI=0.80-4.07) and the recessive genetic model (T/T vs. C/C+T/C: OR=1.91, 95%CI=0.89-4.12). In the stratified analysis by ethnicity, genotyping method and source of control, no significantly association was found. Publication bias was not detected in the included studies.

Meta-analyses of the available data showed that the association between TGF-β1-509C/T polymorphism and susceptibility of endometriosis was not significant. More studies are needed to elucidate its role in endometriosis.