More Sensitive "Electronic Nose" Detects Lung Cancer From Breath

Barbara Boughton

August 03, 2009

August 3, 2009 (San Francisco, California) — Progress made in the development of an "electronic nose" that can detect lung cancer from a patient's breath was detailed here at the at the 13th World Conference on Lung Cancer (WCLC), organized by the International Association for the Study of Lung Cancer. In a press conference, lead researcher Nir Peled, MD, PhD, from the University of Colorado Cancer Center in Denver, predicted that such a test could be ready for the clinic in a few years.

The technology behind these tests relies on the detection of volatile organic compounds (VOCs) in the breath of lung cancer patients. However, the origins of these VOCs have been unclear.

Using nanotechnology, the researchers found that specific VOCs in the breath of lung cancer patients arise from a metabolic pathway in tumor cells. They hope this information can be used to develop a test that can pinpoint VOCs in different kinds of cancers with more accuracy than ever before, according to Dr. Peled and colleagues.

In their study, the researchers grew nonsmall-cell lung cancer (NSCLC) lines, small-cell lung cancer lines, and pancreatic cancer cell lines, and compared them with controls. Gas-chromatography mass spectrometry was used to analyze the VOCs in the cancerous and normal cell lines; the researchers also tested the cells with an electronic nanotechnology "nose" using 18 sensors. Each VOC produces a different signal from the sensors, Dr. Peled said. The sensors are so tiny that thousands will fit on a human hair, he added. "Our aims were to track the source of the smells in the exhaled breath of cancer patients, and to find what compounds are unique or common to each kind of cancer," he said.

The researchers found several VOCs that were unique to each type of cancer cell tested (NSCLC, SCLC, and pancreatic). Their nanotechnology-based sensors could distinguish the cancers with a high degree of sensitivity. For example, NSCLC had 5 unique VOCs, and 3 of them were isolated in the breath of more than 90% of NSCLC patients tested by the researchers.

Dr. Peled acknowledged that "sniff tests" for cancer have received much publicity in recent years. Dogs can sniff out people with cancer, but their sensitivity is only 35% to 40%. In 2007, a study on a breath test for cancer was published by Cleveland Clinic researchers, but the test could only identify 3 of 4 people with lung disease or lung cancer (Thorax. 2007;62:565-568). Other researchers are developing an electronic nose for skin cancer, and have been successful in using nanotechnology to identify odor profiles for basal cell carcinoma.

The Denver group hopes to develop a more accurate and sensitive test. Dr. Peled was collaborating with Hossam Haick, PhD, and his team from the Technion Department of Chemical Engineering and the Russell Berrie Nanotechnology Institute in Haifa, Israel. Their next step is animal and human studies, which they have already begun.

Whether or not a sniff test for lung cancer will ever become a reality is still open to question. "The technology for detecting VOCs in cancer patients' breath has improved considerably," said Paul Bunn, MD, director of the University of Colorado Cancer Center and executive director of the International Association for the Study of Lung Cancer. "Collecting the sample is easy — what's complex is the analysis." Dr. Bunn noted that larger trials with more patients will be needed before any sniff test for lung cancer becomes a usable diagnostic tool. "Although the researchers hope to have a test in a few years, no one will be surprised if that doesn't happen," he said.

Dr. Peled and Dr. Bunn have disclosed no relevant financial relationships.

13th World Conference on Lung Cancer (WCLC): Abstract B3.5. Presented August 2, 2009.