Mechanisms of Immunosurveillance for Lung Cancer

Research has shown that different strains of mice possess varying susceptibility to lung cancer. C3H and C57BL6 mice are highly resistant to lung cancer, whereas A/J and 129 mice are very susceptible to lung cancer. Data from our lab shows that the mice have different numbers of natural killer (NK) cells as well as different characteristics of those cells. C3H and C57BL6 mice have higher numbers of NK cells as well as higher expression of CD11b, whereas A/J and 129 mice have lower numbers and lower expression. These findings justify parallel investigation of NK cells in human populations resistant and susceptible to lung cancer. Through blood samples, circulating NK cells can be counted and phenotypically analyzed. Smoking can be used as a factor to establish lung cancer risk. Additionally, non-smokers suffering from lung cancer provide an opportunity to investigate whether lung cancer patients have lower abundance of NK cells and lesser expression of CD11b, independent of the effects of smoking. Objective: The main goal of this study is to investigate the quantitative and phenotypic differences in circulating NK cells among human populations. Participants will be classified as heavy smokers (HS), non-smokers (NS), those suffering from lung cancer (LC), and those free from lung cancer (NC). Hypothesis #1: NS/LC participants will have fewer NK cells and lower expression of CD11b compared to HS/NC and NS/NC participants. Hypothesis #2: NS/LC participants will have more numerous NK cells and higher expression of CD11b compared to HS/LC participants.