DCAMLK1 is a Ca2+ - ca/modulin (CaM) - dependent protein kinase that is a marker of stem cells in colonic crypts. Mutations within the stem cell population are thought to be responsible for the development of most colorectal carcinomas and studies have shown that DCAMLK1 is highly expressed in these tumors. Since the lung is an embryological development of the foregut, the investigators speculate that DCAMLK1 will also be upregulated in lung cancers.

The aim of this pilot study is to measure DCAMLK1 levels in the blood of patients with suspected malignant and benign lung diseases, and to correlate DCAMKL1 levels with smoking status.

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.

Previous work has showed that DCAMLK1 is not detectable in the blood of healthy non smoking individuals. To determine whether smoking and or pulmonary inflammation induce DCAMLK1 expression, the investigators will obtain serum samples from 20 control patients with lung disease who are seen in the Chest Clinic at the Oklahoma City VAMC. Smoking histories will be obtained for all participants and DCAMLK1 levels will be correlated with smoking status.

Inclusion Criteria:

• >45 years of age

Exclusion Criteria:

• Unable to provide informed consent