2020 LCRF Research Grant on Disparities in Lung Cancer
Chengguo Xing, PhD
University of Florida
Contributions of tobacco exposure, NNK, and stress to lung cancer risk disparities between AA and CA male smokers
In the US, one in every 16 people will be diagnosed with lung cancer in their lifetime with a poor survival. Lung cancer risk disparities are also evident that African American (AA) male smokers have the highest risk. The reasons behind it remain to be determined. Given the limited success in lung cancer early diagnosis and clinical management, understanding why AA male smokers have the highest risk is urgent. The insight will help identify new opportunities for more effective lung cancer management. Specifically, the knowledge would guide the identification of individuals with high risk of lung cancer, the implementation of focused early diagnosis among those high-risk individuals, and the development of personalized precision prevention.
Tobacco exposure is the key risk factor for lung cancer. The survey of cigarette per day (CPD) to estimate tobacco exposure as a risk predictor has limitations, such as no consideration of the depth of tobacco inhalation and second-hand exposure. At the same time, tobacco exposure does not equate to carcinogen bioactivation, one root cause of cancer. NNK is the best-characterized, tobacco-specific, lung carcinogen with plenty of human data to support its causing role in human lung cancer incidence. Its uptake and bioactivation need to be quantified for lung cancer risk prediction. In addition, mental stress, such as anxiety, depression and psychosocial stress, have been reported to increase cancer risk, particularly lung cancer, in epidemiological studies but quantitative analysis is generally lacking. The differences in tobacco exposure, tobacco carcinogen NNK uptake, NNK activation, and mental stress (physiological and psychosocial) likely collectively contribute to the increased lung cancer risk among AA male smokers. This proposal will quantify these risk factors and develop an integrated lung cancer risk factor, which is expected to better predict lung cancer risk and differentiate its disparities in AA male smokers.