Association studies of CYP1A1 and GSTM1 polymorphisms with esophageal cancer risk: evidence-based meta-analyses.
OBJECTIVE
Previous studies have implicated cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) polymorphisms as risk factors for various cancers. A number of studies have been devoted to the association of CYP1A1 or GSTM1 polymorphism with susceptibility to esophageal carcinoma and have yielded conflicting results. We undertook this study to assess possible associations of esophageal cancer risk with CYP1A1 genetic variation and GSTM1 null genotype, respectively.


METHODS
We conducted a search in MEDLINE, EMBASE and Chinese National Knowledge Infrastructure (CNKI) without a language limitation, covering all papers published until May 2008. The associated literature was acquired through deliberate searching and selected based on the established inclusion criteria for publications.


RESULTS
Ultimately, 26 studies met the included criteria and thus were selected. Relevant data were extracted and further analyzed using systematic meta-analyses. Results showed that the overall OR for CYP1A1 Msp1 polymorphism was 1.24 (95% CI = 0.84-1.83). Restricting analyses to ethnic groups and histological groups, data failed to show a correlation between CYP1A1 Msp1 polymorphism and esophageal cancer risk. Overall OR for CYP1A1 exon7 polymorphism was 1.37 (95% CI = 1.06-1.77), and subgroup analyses showed that CYP1A1 exon7 polymorphism increases esophageal cancer risk in Asians but not in Caucasians. As for GSTM1 deficiency, the overall OR was 1.20 (95% CI = 0.96-1.49), and further subgroup analyses failed to show a marked association of GSTM1 deletion with esophageal cancer.


CONCLUSIONS
Results of the present study suggest that CYP1A1 exon7 polymorphisms may be a risk factor for esophageal cancer in Asians but not in Caucasians, whereas neither CYP1A1 Msp1 nor GSTM1 polymorphism was associated with increased susceptibility to esophageal cancer.
Zhuo
Wen-Lei
WL
Institute of Cancer, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
Zhang
Yun-Song
YS
Wang
Yan
Y
Zhuo
Xian-Lu
XL
Zhu
Bo
B
Cai
Lei
L
Chen
Zheng-Tang
ZT
D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics*; D004938:Esophageal Neoplasms / Q000453:epidemiology / Q000235:genetics*; D005091:Exons / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics*; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D011110:Polymorphism, Genetic
D019363:Cytochrome P-450 CYP1A1; D005982:Glutathione Transferase