A Breath Of Fresh Air For Diagnostics
In the scary world of serious illness, early detection is crucial. The sooner someone knows he has cancer or rheumatoid arthritis, for example, the sooner they can get moving with treatment. Early detection means a greater likelihood of a good outcome, saved time and money and maybe even less heartache.
Sadly, diagnosing disease can be grueling, painful, and time consuming. Undoubtedly, patients know this best. However, medical researchers know it too. Some of them are working to improve the process. Maybe you’ve heard of liquid biopsies – the detection of cancer in a drop of blood or a urine sample rather than instead of a traditional biopsy. If you think that’s amazing, what about a breath biopsy? Think of it as a cancer breathalyzer. This WEEKLY takes a closer look at this innovative approach to detecting illness.
Term Of The Week: Volatile Organic Compound
Here’s a possibly new perspective on that peanut butter sandwich or banana you may have just munched. It may have tasted like food but really it’s fuel. Specifically, it’s energy that our bodies use to power cellular function courtesy of a series of chemical reactions. The whole miraculous affair, cellular metabolism, produces and ultimately releases organic (carbon-containing) compounds into our blood. When the blood passes through our lungs, some compounds are exchanged into the lungs, and then exhaled. Once we breathe the stuff out, scientists call them volatile organic compounds (VOCs). Our breath contains more than a thousand VOCs, or metabolites, as they are also called.
The Disruptive Rhythm Of Disease
Disease affects our cellular metabolism, changing which VOCs it produces. The unique VOC “fingerprint” of different maladies may help researchers identify patients based on metabolic changes – many of which appear before other symptoms.
Science has long known that cancer cells have irregular metabolisms. For example, they consume glucose at a rate as much as two hundred times greater than that of healthy counterparts. Malignant cells also use anaerobic (without oxygen) metabolic pathways, rather than the aerobic – with oxygen –- pathways preferred by healthy cells. Cancer’s altered cellular rhythm manufactures different metabolic by-products, some of which can be detected as VOCs. Other diseases produce altered VOCs too, including diabetes, liver impairment, kidney disease, asthma, cystic fibrosis, rheumatoid arthritis, atherosclerosis, and tuberculosis.
These metabolic changes that come with illness underpin the whole notion of the disease breathalyzer.
Breathing Life Into VOC Diagnostics
Owlstone Medical (Cambridge, U.K.) has begun to develop a diagnostic based on VOCs with their ReCIVA Breath Sampler. During testing, a patient inhales normally from a standardized air supply, to make sure that the source of air doesn’t impact the results. The air is then exhaled into a breath biopsy cartridge, which captures the patient’s VOCs. The cartridge is then sent to a lab for analysis with Owlstone’s proprietary Field Asymmetric Ion Mobility Spectrometry (FAIMS).
What’s Not To Love?
Breath biopsies possess a unique, obvious advantage over other diagnostic methods. No pain, no discomfort. They don’t even require a finger prick! The test is also extremely sensitive – detecting even miniscule concentrations of suspicious VOCs. That’s because it takes our entire blood supply only about a minute to circulate throughout the body. Yup, sixty seconds. The sampling period for breath biopsies is typically ten minutes. That allows all of our blood to get sampled several times, making the discovery of a questionable VOC extremely likely.
In The Wind
Unfortunately, no breath biopsies are on the market yet. However, Owlstone is already conducting several clinical trials to demonstrate its validity:
- LuCID (Lung Cancer Indicator Detection): In partnership with the U.K. National Health Service, this trial has identified unique VOCs in lung cancer patient’s exhalations. Phase II aims to validate the detection of these biomarkers in clinical practice.
- STRATA (Stratification of Asthma Treatment by Breath Analysis): This study is examining how VOCs may help select the best asthma treatment.
- InTERCEPT: This study focuses on identifying and validating VOCs to detect colorectal cancer.
- PAN (PAN-cancer early detection): In partnership with Cancer Research UK, this trial aims to identify VOCs associated with many different cancers, including bladder, breast, head and neck, kidney, esophageal, pancreas, and prostate.
Cocktail Fodder: Catching A Whiff Of Cancer
Whether you consider dogs best friend material or merely tolerate them, take one minute to appreciate their amazing snouts. Canine noses contain 220 million scent receptors. Puny little human noses only boast about five million. Their superior scent-detection enables these super-sniffers to find lost people, explosives and contraband of all sorts. Scientists have also discovered that dogs can sniff out some kinds of cancer. That’s because VOCs are present in all of our emissions! Breath, sweat, saliva and, well, you know. Fido definitely knows that cancer stinks!
Emily Burke, PhD has worked in biopharma for 20 years, gaining science writing experience at The Scripps Research Institute and ISIS Pharmaceuticals. As a PhD molecular biologist, she is passionate about advancing the public’s understanding of science. In addition to being a self-proclaimed “science geek,” she is regularly asked to speak at international scientific meetings worldwide. When not teaching and writing the WEEKLY for Biotech Primer, Dr. Burke swims with her swim club and performs regularly on the improv circuit in San Diego.