"Rationale. Free circulating plasma DNA has emerged as a potential biomarker for early lung cancer detection. In a previous case-control study we have shown that high levels of plasma DNA are a strong risk factor for lung cancer. Objective. To assess the diagnostic performance and prognostic value of plasma DNA levels in a cohort of 1035 heavy smokers monitored by annual spiral-CT for 5 years. Methods. Plasma DNA levels were determined through real-time quantitative PCR at baseline and at time of lung cancer diagnosis.

"Serum-based diagnosis offers the prospect of early lung carcinoma detection and of differentiation between benign and malignant nodules identified by CT. One major challenge toward a future blood-based diagnostic consists in showing that seroreactivity patterns allow for discriminating lung cancer patients not only from normal controls but also from patients with non-tumor lung pathologies. We addressed this question for squamous cell lung cancer, one of the most common lung tumor types.

"Dysregulated expression of microRNAs (miRNAs) in various tissues has been associated with a variety of diseases, including cancers. Here we demonstrate that miRNAs are present in the serum and plasma of humans and other animals such as mice, rats, bovine fetuses, calves, and horses. The levels of miRNAs in serum are stable, reproducible, and consistent among individuals of the same species. Employing Solexa, we sequenced all serum miRNAs of healthy Chinese subjects and found over 100 and 91 serum miRNAs in male and female subjects, respectively.

"Early detection and optimal treatment are the most effective means to improve cancer mortality. Mass screening for cancer has yielded a marked reduction of cancer mortality in the United States. Simple and effective methods are expected for screening of malignancy. Hematoporphyrin derivatives (HPDs) are known to accumulate in cancer cells; thus, HPD has been used for local diagnosis and photodynamic therapy of cancer. The lymphocytes of cancer patients also demonstrate the active uptake of HPD and this phenomenon has been applied for the diagnosis of cancer.

RATIONALE: Our group has recently demonstrated the possibility of studying microsatellite alterations (MAs) of 3p in the DNA of exhaled breath condensate (EBC) of patients with non-small cell lung cancer (NSCLC). OBJECTIVES: To verify whether MAs analyzed in DNA from EBC reflect a profile of alterations present in tumor tissue of NSCLC. METHODS: Fifty-nine subjects undergoing histologic diagnosis for clinical suspicion of lung cancer entered the study: 41 were found to have NSCLC and 18 to have nonneoplastic diseases.