title: No association between TGFB1 polymorphisms and late radiotherapy toxicity: a meta-analysis.
abstract: BACKGROUND
  Transforming growth factor-beta 1 (TGF-β1) protein may be multifunctional and related to the development of fibrosis, induction of apoptosis, extracellular signaling and inhibition of proliferation in response to radiation-induced DNA damage. Several studies have investigated associations between single nucleotide polymorphisms (SNPs) in the TGFB1 gene and risk of late radiation-induced injury of normal tissue, but the conclusions remain controversial.
  
  
  METHODS
  We searched three electronic databases (i.e., MEDLINE, EMBASE and EBSCO) for eligible publications and performed a meta-analysis assessing the association of three commonly studied SNPs in TGFB1 (i.e., rs1800469, rs1800470 and rs1800471) with risk of late radiation-induced injury of normal tissue.
  
  
  RESULTS
  We finally included 28 case-only studies from 16 publications on aforementioned SNPs in TGFB1. However, we did not find statistical evidence of any significant association with overall risk of late radiotherapy toxicity in the pooled analysis or in further stratified analysis by cancer type, endpoint, ethnicity and sample size.
  
  
  CONCLUSIONS
  This meta-analysis did not find statistical evidence for an association between SNPs in TGFB1 and risk of late radiation-induced injury of normal tissue, but this finding needs further confirmation by a single large study.
authors.affiliation: Department of Oncology, Xin Hua Hospital affiliated To Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Mei-Ling
authors.initials: ML
authors.lastname: Zhu
authors.forename: MengYun
authors.initials: M
authors.lastname: Wang
authors.forename: Ting-Yan
authors.initials: TY
authors.lastname: Shi
authors.forename: Qiao-Xin
authors.initials: QX
authors.lastname: Li
authors.forename: Pan
authors.initials: P
authors.lastname: Xi
authors.forename: Kai-Qin
authors.initials: KQ
authors.lastname: Xia
authors.forename: Leizhen
authors.initials: L
authors.lastname: Zheng
authors.forename: Qing-Yi
authors.initials: QY
authors.lastname: Wei
mesh_terms: D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D011832:Radiation Injuries / Q000235:genetics*; D011878:Radiotherapy / Q000009:adverse effects*; D013997:Time Factors; D053773:Transforming Growth Factor beta1 / Q000235:genetics*
chemical_list: C508960:TGFB1 protein, human; D053773:Transforming Growth Factor beta1