title: Null genotypes of GSTM1 and GSTT1 contribute to risk of cervical neoplasia: an evidence-based meta-analysis.
abstract: OBJECTIVE
  Glutathione S-transferases (GSTs) are multifunctional enzymes that play a key role in the detoxification of varieties of both endogenous products of oxidative stress and exogenous carcinogens.
  
  
  METHODS
  In this meta-analysis, twenty-five studies were identified by searching PubMed, EMBASE, ISI Web of Science and CBM databases: 23 evaluated GSTM1 and 19 evaluated GSTT1. Crude odds ratios with corresponding 95% confidence intervals were used to estimate the association between GSTM1 and GSTT1 polymorphisms and risk of cervical neoplasia. Subgroup analyses were conducted by pathological history, ethnicity, source of DNA for genotyping, quality score, and matching variable.
  
  
  RESULTS
  The null genotypes of GSTM1 and GSTT1 polymorphisms were associated with a significantly increased risk of cervical neoplasia (for GSTM1: OR = 1.40; 95%CI, 1.19-1.65; for GSTT1: OR = 1.30; 95%CI, 1.05-1.62, respectively). Subgroup analyses showed that the null genotype of GSTM1 increased the risk of cervical neoplasia in Asians, studies with DNA isolation from white blood cells and tissue samples, both high and low quality studies, and matched studies. In GSTM1-GSTT1 interaction analysis, individuals with dual null genotype were associated with a significantly increased risk of cervical neoplasia (OR = 1.72; 95%CI, 1.18-2.51).
  
  
  CONCLUSIONS
  These findings indicate that GSTM1 and GSTT1 polymorphisms, particularly GSTM1-GSTT1 interaction, may play critical roles in the development of cervical neoplasia. A conservative manner should be adopted to interpret these results because of obvious heterogeneity between-study, unadjusted data, and relatively small sample size in this meta-analysis. Well designed studies with larger sample size are of great value to confirm these results.
authors.affiliation: Laboratory of Molecular and Translational Medicine, West China Institute of Women and Children's Health, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
authors.forename: Lin-Bo
authors.initials: LB
authors.lastname: Gao
authors.forename: Xin-Min
authors.initials: XM
authors.lastname: Pan
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Li
authors.forename: Wei-Bo
authors.initials: WB
authors.lastname: Liang
authors.forename: Peng
authors.initials: P
authors.lastname: Bai
authors.forename: Li
authors.initials: L
authors.lastname: Rao
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Su
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Bin
authors.initials: B
authors.lastname: Zhou
authors.forename: Yong-Gang
authors.initials: YG
authors.lastname: Wei
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
mesh_terms: D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D016017:Odds Ratio; D011110:Polymorphism, Genetic / Q000235:genetics; D011485:Protein Binding / Q000235:genetics / Q000502:physiology; D002583:Uterine Cervical Neoplasms / Q000201:enzymology / Q000235:genetics*
chemical_list: D005982:Glutathione Transferase; C413545:glutathione S-transferase T1