title: Phase I and II enzyme polymorphisms as risk factors for Barrett's esophagus and esophageal adenocarcinoma: a systematic review and meta-analysis.
abstract: Although several studies have examined the association between phase I/II enzyme polymorphisms and esophageal adenocarcinoma (EAC) and/or Barrett's esophagus (BE), their overall findings remain unclear. We performed a systematic review and meta-analysis to determine whether phase I/II polymorphisms are independent risk factors for either BE or EAC. We employed keyword searches in multiple databases to identify studies published before October 1, 2007. Single-nucleotide polymorphisms (SNPs) examined in > or =3 studies were meta-analyzed to obtain a pooled estimate of effect. Meta-analysis suggested the minor allele for GSTP1 Val(105) conveys modest excess risk (odds ratio [OR](BE)= 1.50, 95% confidence interval [CI] 1.16-1.95; OR(EAC)= 1.20, 95% CI 0.94-1.54). No excess risk was observed with GSTM1 null (OR(BE)= 0.77, 95% CI: 0.56-1.08; OR(EAC)= 1.08, 95% CI: 0.79-1.48), GSTT1 null (OR(BE)= 1.35, 95% CI: 0.91-2.01; OR(EAC)= 0.84, 95% CI: 0.48-1.49), or CYP1A Val(462) (OR(EAC)= 0.89, 95% CI: 0.40-1.97). Insufficient data existed to meta-analyze remaining SNPs. Our review identified GSTP1(Ile105Val) as a possible risk factor for BE and EAC in Caucasian males. No excess risk was observed for other phase I/II polymorphisms with sufficient data to meta-analyze. Additional studies are needed to determine if GSTP1 conveys excess risk in females or non-Caucasians and to evaluate other phase I/II polymorphisms.
authors.affiliation: Baylor College of Medicine, Houston, Texas, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Bull
authors.forename: D L
authors.initials: DL
authors.lastname: White
authors.forename: M
authors.initials: M
authors.lastname: Bray
authors.forename: Z
authors.initials: Z
authors.lastname: Nurgalieva
authors.forename: H B
authors.initials: HB
authors.lastname: El-Serag
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology / Q000453:epidemiology* / Q000235:genetics; D001471:Barrett Esophagus / Q000201:enzymology / Q000453:epidemiology* / Q000235:genetics*; D016022:Case-Control Studies; D004938:Esophageal Neoplasms / Q000201:enzymology / Q000453:epidemiology* / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors