p16 Methylation for Smoking Cessation

In the United States during 2007, ~ 213,380 people were expected to be diagnosed with lung cancer, and ~ 160,390 expected to die of the disease. Among those diagnosed with lung cancer, 79% to 90% are cigarette smokers. Overall, ~21% of adults in the U.S. smoke. The most important and cost-effective strategy for the prevention of lung cancer mortality is smoking avoidance and cessation. Smoking cessation is often difficult for smokers to achieve for a variety of reasons including: difficulty with nicotine withdrawal, failure to perceive the benefits of smoking cessation, and failure to perceive the risks associated with smoking. We argue that the most effective biomarkers to affect perceptions of harm, especially for lung cancer, are those that signal progression towards disease development. Prior to the development of lung cancer, there are genetic alterations in the bronchial epithelium. One such alteration is the methylation of the promoter region of Rb-p16 (p16) important in regulation of the G1-S transition of the cell cycle. Prior studies have shown that presence of the promoter methylation of p16 results in a 2-fold increase in risk of developing lung cancer in smokers with evidence of airway obstruction.

Proposed is a pilot study of educating smokers about the role of genetics and lung cancer in Durham VA out-patient clinics. The goal of this pilot study is to assess the interest in study participation from the VA smoking population, as well as to determine the fraction of subjects who will complete the study to power a future larger trial. Interested patients will receive a 15 minute educational presentation on the function of p16 and its role in development of lung cancer. They will then be assessed for airway obstruction by hand-held spirometry followed by review of a questionnaire assessing their understanding of the presented information, their concern for developing lung cancer, and their desire to quit smoking. All patients will be offered smoking cessation assistance at this point. Enrolled patients will then be given 3 sputum cups to take home and return with morning sputum samples by mail. Samples will be assessed for evidence of p16 methylation and patients will be informed of the results. Follow-up phone interviews will be performed at 2 to 4 weeks after patients have received their results by mail to assess their understanding of the results, and their desire to stop smoking. A final phone interview will occur approximately 3 months after the sputum testing to assess attempts to stop smoking as well as the patients continued understanding of their test results. Patients will be compensated a total of $40.00 for completing the study. For purposes of this pilot, we are interested primarily in the descriptive statistics (e.g., frequencies) associated with the outcome of each objective (e.g., how many expressed interest, how many returned the sputum samples).