Lung cancer is the most common cancer in many countries, and tumors are usually diagnosed at a late stage resulting in a 5 year survival rate of only 5%. An advanced X-ray imaging technique, low dose spiral computed tomography (CT) scanning, can detect tumors when they are still small and treatment can be more successful, but its use for routine screening of high risk patients is controversial. Celera’s proteomics program has identified a panel of proteins found on the surface of lung cancer cells and also in serum, and is testing their potential to identify people who might benefit from a CT scan, or to confirm that a CT image is very likely to be a tumor and should be biopsied.