Early detection of lung cancer: Protein biomarkers in exhaled air

Lung tumors are the number one cause of death among cancer patients, and one cancer in three is lung cancer. Each year, there are 50,000 new cases of the disease in Germany alone. The earlier a tumor can be detected, the greater the chance of healing the patient. But early detection is difficult. In its initial stages, the tumor-related complaints resemble chronic inflammatory reactions.

To get a more complete diagnosis, the patient must undergo an X-ray examination or an bronchoscopy. The last procedure often involves irritation of the lung or removal of tissue samples and, as a result, it is particularly unpleasant for the patient undergoing the procedure.

In recent years, scientists at the Fraunhofer Institute for Cell Therapy and Immunology IZI in Leipzig have teamed up with colleagues at the University Clinic of Leipzig to develop a procedure that can detect special protein biomarkers in exhaled air. The presence of biomarkers suggests the presence of tumor cells in the lung. In a project sponsored by the Federal Ministry of Education and Research (BMBF), the specialists want to work with partners in industry -- two medium-sized companies in the regional -- to produce a first prototype that can then be further developed into a diagnostic tool that can be used in practice.

"Since 2006, working with the working groups of Professor Hubert Wirtz and Professor Ulrich Sack of the University Clinic, we first identified various biomarkers that are particularly well-suited for the identification of lung-cancer cells," notes Dr. Jörg Lehmann, head of the Cell Engineering/GLP Unit at IZI. "The main difficulty lies in finding a reliable way to distinguish cancer from chronic inflammatory disease."

The researchers have developed a laboratory method for reliably identifying biomarkers specific to lung cancer in special samples of exhaled air. To accomplish this, the patient must breathe into a piece of equipment for roughly 20 minutes. The exhaled breath condensate is then evaporated. Biomarkers are detected by means of special antibodies that recognize substances such as the protein VEGF. This protein is responsible for stimulating the growth of new blood vessels. This laboratory method is still too "elaborate and expensive" for normal everyday use, the scientist adds.

"Working in our joint project, the goal for the next two years is to produce a prototype that will then be validated in a clinical-diagnostic study and further developed to the production stage," Lehmann says.

In their new testing platform, the scientists have actually applied two new developments: in addition to the method enlisting protein biomarkers to identify cancer cells, they also make use of the antibody specially developed for this procedure. This way, within just a few years, every physician investigating a suspicion of lung cancer can use the diagnostic platform right in his or her practice to test whether there really is a tumor and quickly initiate treatment.