CYP2A13, CYP2A6, and CYP2A7 mRNA were lower in smokers
than in non-smokers
Smokers, vs non-smokers, had significantly lower levels of CYP2A13,
CYP2A6 and CYP2A7 mRNA in the small airway epithelium of the lung; this
finding was replicated in two GEO datasets (Figure 3). Smoking is an
established inducer of CYP1A2 mRNA and thus was used as a positive
control for the assessment within this data set of the association of
smoking status and viability of samples (Wei et al., 2002). Smokers, vs
non-smokers, had significantly higher CYP1A2 mRNA in both datasets.
In GSE11784, smoking quantity was assessed, using pack-year data,
against levels of CYP2A13, CYP2A6 and CYP2A7 mRNA in the small airway
epithelium of the lung. There was a significant, albeit weak, negative
correlation between CYP2A13 (r = –0.178), CYP2A6 (r = –0.307) and,
CYP2A7 (r = –0.198) mRNAs and pack-years smoked, suggesting a potential
dose-dependent association between smoking exposure and CYP2A mRNA
levels in smokers’ lungs.