In the investigators' preliminary study DCAMKL1 antigen was detected not only in malignant tissue, but also in BAL fluid from patients with benign lung disease. This suggests that DCAMKL1 expression might be induced by smoking or benign lung diseases. To examine this hypothesis, the investigators will compare DCAMLK1 expression in blood from patients with lung cancer to controls who are current or former smokers with benign lung disease.