Electronic cigarettes (e-cig) are increasingly popular among adult smokers and adolescent never smokers. Chemical analyses of e-cig vapor and liquid have shown the presence of many of the same carcinogens as those found in cigarette smoke, albeit in generally lower concentrations. However, the carcinogenic potential of e-cig has not been investigated in e-cig users (otherwise known as 'vapers'). The investigators will investigate the cancer-causing potential of e-cig use as compared to cigarette smoking by quantifying molecular changes linked to risk of cancer in smokers who switch to e-cig use vs. those who maintain their smoking habits. Leveraging a source population for ongoing studies on e-cig, the investigators will recruit smokers who are interested in switching to e-cig use, and two control groups of non-vapers, including smokers and nonsmokers who do not intend to change their smoking and nonsmoking status, respectively (n = 50, each group). Smokers consenting to switch completely to e-cig will be assigned to a 3-month intervention with a standard e-cig with fully described product characteristics. Control groups will maintain their smoking/nonsmoking habits during the intervention. At weekly intervals, the investigators will verify participants' compliance through personal interviews, CO breath tests, cotinine quantification, and vaping/smoking topography measurements. The investigators will use a non-invasive brushing technique to collect oral cells from the inside of the cheeks of all participants at baseline and every 2 weeks, afterwards. The investigators will use an integrative 'multi-omics' approach complemented with single-locus/gene validation analyses to detect temporal changes in the genome, epigenome, and transcriptome relevant to cancer in the oral cells of the participants as the intervention progresses.
This project will address a growing public health concern, namely, the health risks or benefits of e-cig use relative to cigarette smoking. The investigators will use biomarkers of early effects of relevance to cancer to determine the carcinogenic potential of e-cig use relative to cigarette smoking in oral epithelium, which is a target tissue for smoking-associated cancer. The study population will consist of one group of smokers who are interested in switching to e-cig use (Grp 1), one group of smokers who do not intend to change their smoking habits (Grp 2), and one group of non-users who would like to maintain their nonsmoking non-vaping status (Grp 3); The total number of participants in this project is 150 (n = 50, each group). The investigators will use an integrative 'multi-omics' approach complemented with single-locus/gene validation analyses to detect temporal changes in the genome, epigenome, and transcriptome relevant to cancer in the oral cells of the participants as the intervention progresses.