2.1. Patient Cohort
The study population comprised 100 newly diagnosed and previously untreated lung cancer patients and 100 lung cancer-free control samples. All samples used in the present study were provided by the biobank of the Molecular Epidemiology group headed by Andrea Gsur at the Medical University, Department of Medicine I, Institute of Cancer Research, Vienna. Cases were recruited from two pulmonological centers in Vienna and Lower Austria. Regarding histological data, cases were further classified as 25 small-cell lung carcinoma (SCLC), 25 squamous cell carcinoma (SqLC), 25 large cell carcinoma (LCLC), and 25 adenocarcinoma (AdCa). Seventy-two hospital-based controls were derived from the Department of Orthopedics of the Medical University of Vienna. Only subjects with negative chest radiography and no history of malignant disease were selected as controls. Additionally, 28 controls were recruited from the colorectal cancer screening project “Burgenland Prevention Trial of Colorectal Cancer Disease with Immunological Testing” (B-PREDICT). These individuals underwent colonoscopy and did not show any pathological finding. All participants were Austrian Caucasians. Clinical characteristics of the samples are summarized in Table 1. 
Blood was collected using Vacuette BD vacutainer® tubes (Greiner Bio-One, Kremsmünster, Austria) with sodium heparin as anticoagulant. After collection, heparinized blood was centrifuged at 2000 × g for 10 minutes and plasma was removed from the cell pellet and stored at −80 °C. Written informed consent was obtained from all participants and research protocols were approved by the institutional review boards.
microarrays-04-00162-t001_Table 1 Table 1  Clinical characteristics of the study population.   a At time of diagnosis.

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