CYP2A6 deletion polymorphism is associated with decreased susceptibility of lung cancer in Asian smokers: a meta-analysis

Tumour Biol. 2013 Oct;34(5):2651-7. doi: 10.1007/s13277-013-0815-y. Epub 2013 May 7.


Cytochrome P450 2A6 (CYP2A6) is an enzyme involved in the metabolism of some tobacco carcinogens, which is an important risk factor of lung cancer. Among CYP2A6 allelic variants, CYP2A6*4 presents a whole gene deletion that accounts for the majority of poor metabolizer. In this study, a meta-analysis was performed to assess the association between CYP2A6*4 and risk of lung cancer. Literature searches were conducted to identify peer-reviewed manuscripts published up to December 20, 2012. Pooled odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were calculated in a fixed-effects model and a random-effects model when appropriate. Eight eligible studies with 3,203 lung cancer cases and 2,839 controls were included in this study. Overall, no significant association was observed in CYP2A6*4 with the risk of lung cancer under any genetic model for all samples after correction. However, subgroup analysis showed that significant associations were observed in Asian with pooled OR (95 %CI) of 0.761 (0.672-0.861) for allele comparison, 0.769 (0.668-0.886) for dominant model, and 0.522 (0.359-0.760) for recessive model. Furthermore, after stratifying Asian samples according to smoking status, significant associations were only observed in smokers with pooled OR (95 %CI) of 0.713 (0.607-0.838) for allele comparison, 0.720 (0.596-0.869) for dominant model, and 0.444 (0.275-0.715) for recessive model. This meta-analysis suggests that the CYP2A6*4 polymorphism was associated with susceptibility of lung cancer for smokers in Asian. The whole gene deletion of CYP2A6 might decrease the risk of tobacco-related lung cancer in Asian.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aryl Hydrocarbon Hydroxylases / genetics*
  • Asian Continental Ancestry Group
  • Case-Control Studies
  • Cytochrome P-450 CYP2A6
  • Disease Resistance
  • Gene Deletion*
  • Gene Frequency
  • Genetic Association Studies
  • Genetic Predisposition to Disease
  • Genotype
  • Humans
  • Lung Neoplasms / genetics*
  • Polymorphism, Genetic*
  • Smoking / adverse effects*
  • Smoking / genetics


  • Aryl Hydrocarbon Hydroxylases
  • CYP2A6 protein, human
  • Cytochrome P-450 CYP2A6