Are Smokers Switching to Vaping at Lower Risk for Cancer? (Electronic Cigarettes and Cancer Risk)

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.

Inclusion Criteria:

- Being male or female between the ages of 22-55;

- Being able to read and write in English and understand and give informed consent;

- Giving consent to strictly follow the study protocol throughout the study;

- Not planning to move, take an extended vacation, or undergo surgery during the study;

- Reporting smoking of > 5 manufactured cigarettes per day for at least 1 year
(applicable to participants who will undergo intervention with e-cig (Grp 1) or
continue to smoke (Grp 2) only); and

- Presenting with an expired air CO measurement of > 7 parts per million (ppm) at
baseline (applicable to participants who will undergo intervention with e-cig (Grp 1)
or continue to smoke (Grp 2) only).

Exclusion Criteria:

- Having oral infection/inflammation, gum disease, dental decay, immune system
disorders, diabetes, respiratory diseases (e.g., asthma), or kidney diseases;

- Having any unstable or significant medical condition (e.g., symptomatic heart
conditions) in the past 12 months ;

- Having body mass index < 18 kg/m2 or > 40 kg/m2

- Being pregnant or having a baby in the past 12 months;

- Having uncontrolled mental illness or substance abuse (e.g., alcoholism) or inpatient
treatment for those conditions in the past 12 months;

- Having used recreational or illicit drugs in the past 3 months;

- Having used any medication known to induce/inhibit CYP450 2A6 enzyme;

- Having any known allergy to propylene glycol/vegetable glycerin (applicable
participants who will undergo intervention with e-cig (Grp 1) only); and

- Having another member of household participating in the study.