The electronic nose, a device long used for safety and quality control in the food, wine and perfume industries, also can be used to detect early evidence of lung cancer, according to research conducted at The Cleveland Clinic.
Known as the Cyranose, the electronic nose is a hand-sized device that uses biosensor technology to produce a “smellprint” of the volatile organic compounds that comprise human breath and other scents.
Led by Serpil Erzurum, M.D., chairman of the Department of Pathobiology at the Cleveland Clinic Lerner Research Institute, researchers speculated the electronic nose could be used to detect and distinguish between lung diseases, particularly lung cancer. Testing their theory, they found the exhaled breath of lung cancer patients had specific characteristics that, in fact, could be detected with the device. Their findings will be published in the American Journal of Respiratory Medicine later this spring.
“Our work indicates that the electronic nose can be used as a non-invasive tool for the early diagnosis of lung cancer and to monitor the effectiveness of treatment on lung cancer patients,” Dr. Erzurum said. “Use of the electronic nose could enable physicians to determine the appropriate course for a lung cancer patient’s treatment at an earlier stage, rather than after the cancer has spread to other parts of the body and is more difficult to treat. The small, portable nature of the electronic nose also makes it easy to use in physician offices and outpatient settings.”
Breath of lung cancer patients is detectably different than breath of healthy patients.
In their study, Cleveland Clinic researchers examined the exhaled breath of 14 lung cancer patients and 45 healthy patients. The electronic nose was programmed to detect certain characteristics in breath and used algorithms to create patterns viewable on a computer screen. Researchers found the pattern characterizing the breath of lung cancer patients was distinctly different from that of healthy patients and of people with other lung diseases.
Breath is not the only promising target for the development of fast and less invasive methods for detecting diseases. Back in December 2004 David Wong and colleagues at UCLA found human messenger RNA (mRNA which is made from DNA to be translated into proteins) in saliva. Wong has been able to show that salivary mRNA can be used to detect some types of cancer.
The UCLA team collected saliva and blood from 32 patients with primary oral squamous cell carcinoma and 40 breast cancer patients, and matched each with saliva and blood from otherwise normal subjects. New techniques were developed to halt RNA degradation so the scientists could recover as much mRNA as possible for their samples. In all, the new techniques allowed the scientists to harvest up to 10,000 types of human mRNA from saliva, setting up a comparison test between cancer patients and the normal subjects based on analysis of their genetic "profiles."
"Both serum and saliva exhibited unique genetic profiles," said Wong. "The risk model yielded a predictive power of 95 percent by using only the salivary transcriptome samples and 88 percent by using only serum transcriptome samples for oral squamous cell carcinomas," said Wong. "For oral cancer, salivary transcriptome has a slight edge of that of serum transcriptome analysis."
Messenger RNA can be tested for using chips designed to bind with minute quantities of different mRNA sequences. A single chip can be made to test for the presence of many different mRNA sequences in parallel. Results from such tests will form patterns akin to fingerprints with different diseases having different patterns of mRNAs present.
Wong is director of the UCLA Human Salivary Proteome Project which has as its goal to identify and characterize all the proteins in saliva. But Wong is also working on development of tests for salivary mRNA to detect pathogens, cancers, and other diseases. My guess: mRNA patterns in saliva will become far more important than protein patterns because the mRNA patterns will be much easier to test for.
Watch for a gradual partial replacement of blood tests by breath and saliva tests that will be performed in doctors' offices while you wait. Then watch for the introduction of home saliva and breath tests that can be done cheaply and more often. Expect the mRNA saliva tests to hit the market in this decade. Ditto for breath tests.
|Share |||Randall Parker, 2005 April 27 02:06 AM Biotech Assay Tools|