Smoking and Lung Cancer: The Role of CCND2 Gene Hypermethylation
Author Information
Author(s): Salskov Alexander, Hawes Stephen E., Stern Joshua E., Feng Qinghua, Jordan C. Diana, Wiens Linda, Rasey Janet, Lu Hiep, Kiviat Nancy B., Vesselle Hubert
Primary Institution: University of Washington
Hypothesis
Does tobacco smoke induce DNA hypermethylation as an early event in lung carcinogenesis?
Conclusion
CCND2 hypermethylation is more frequent in ever-smokers and may indicate an early, precancerous change in the lung due to smoking.
Supporting Evidence
- CCND2 hypermethylation was found in 26% of ever-smokers compared to 3% of never-smokers.
- Hypermethylation of CCND2 was associated with increased age and upper lobe sample location.
- APC hypermethylation was also observed in both ever-smokers and never-smokers.
Takeaway
This study found that a gene called CCND2 is changed in smokers' lungs, which might mean that smoking starts to cause problems even before cancer develops.
Methodology
316 lung tissue samples from 151 cancer-free subjects were analyzed for hypermethylation of 19 genes using MethyLight assays.
Potential Biases
The majority of smokers were older and had undergone surgery for emphysema, which may confound results.
Limitations
The study had a small number of never-smokers and all subjects had underlying non-cancer pulmonary diagnoses.
Participant Demographics
151 subjects, including 121 ever-smokers and 30 never-smokers, with a mean age of 61 for ever-smokers and 44 for never-smokers.
Statistical Information
P-Value
p<0.001
Confidence Interval
95% CI = 1.2–2.4 for age, 95% CI = 1.0–3.8 for upper lobe location
Statistical Significance
p<0.001
Digital Object Identifier (DOI)
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