Pilot study of CYP2B6 genetic variation to explore the contribution of nitrosamine activation to lung carcinogenesis

Int J Mol Sci. 2013 Apr 16;14(4):8381-92. doi: 10.3390/ijms14048381.

Abstract

We explored the contribution of nitrosamine metabolism to lung cancer in a pilot investigation of genetic variation in CYP2B6, a high-affinity enzymatic activator of tobacco-specific nitrosamines with a negligible role in nicotine metabolism. Previously we found that variation in CYP2A6 and CHRNA5-CHRNA3-CHRNB4 combined to increase lung cancer risk in a case-control study in European American ever-smokers (n = 860). However, these genes are involved in the pharmacology of both nicotine, through which they alter smoking behaviours, and carcinogenic nitrosamines. Herein, we separated participants by CYP2B6 genotype into a high- vs. low-risk group (*1/*1 + *1/*6 vs. *6/*6). Odds ratios estimated through logistic regression modeling were 1.25 (95% CI 0.68-2.30), 1.27 (95% CI 0.89-1.79) and 1.56 (95% CI 1.04-2.31) for CYP2B6, CYP2A6 and CHRNA5-CHRNA3-CHRNB4, respectively, with negligible differences when all genes were evaluated concurrently. Modeling the combined impact of high-risk genotypes yielded odds ratios that rose from 2.05 (95% CI 0.39-10.9) to 2.43 (95% CI 0.47-12.7) to 3.94 (95% CI 0.72-21.5) for those with 1, 2 and 3 vs. 0 high-risk genotypes, respectively. Findings from this pilot point to genetic variation in CYP2B6 as a lung cancer risk factor supporting a role for nitrosamine metabolic activation in the molecular mechanism of lung carcinogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activation, Metabolic / genetics
  • Aged
  • Cytochrome P-450 CYP2A6 / genetics
  • Cytochrome P-450 CYP2B6 / genetics*
  • Cytochrome P-450 CYP2B6 / metabolism*
  • Feasibility Studies
  • Female
  • Genetic Variation*
  • Genotype
  • Humans
  • Lung Neoplasms / etiology*
  • Lung Neoplasms / genetics
  • Lung Neoplasms / metabolism
  • Male
  • Middle Aged
  • Nerve Tissue Proteins / genetics
  • Nitrosamines / metabolism*
  • Odds Ratio
  • Pilot Projects
  • Receptors, Nicotinic / genetics
  • Risk Factors

Substances

  • CHRNA5 protein, human
  • CHRNB4 protein, human
  • Nerve Tissue Proteins
  • Nitrosamines
  • Receptors, Nicotinic
  • nicotinic receptor subunit alpha3
  • CYP2A6 protein, human
  • CYP2B6 protein, human
  • Cytochrome P-450 CYP2A6
  • Cytochrome P-450 CYP2B6