A study has shown that dogs can use their highly evolved sense of smell to pick out blood samples from people with cancer with almost 97% accuracy. The results could lead to new cancer-screening approaches that are inexpensive and accurate without being invasive.
"Although there is currently no cure for cancer, early detection offers the best hope of survival," said Heather Junqueira, who is lead researcher at BioScentDx and performed the study. "A highly sensitive test for detecting cancer could potentially save thousands of lives and change the way the disease is treated."
Junqueira presented the research at the American Society for Biochemistry and Molecular Biology annual meeting during the 2019 Experimental Biology meeting in Orlando, Florida.
For the study, Junqueira and her colleagues used a form of clicker training to teach four beagles to distinguish between normal blood serum and samples from patients with malignant lung cancer. Although one beagle – aptly named Snuggles – was unmotivated to perform, the other three dogs correctly identified lung cancer samples 96.7% of the time and normal samples 97.5% of the time. Dogs have smell receptors 10,000 times more accurate than humans', making them highly sensitive to odours we can't perceive.
"This work is very exciting because it paves the way for further research along two paths, both of which could lead to new cancer-detection tools," said Junqueira. "One is using canine scent detection as a screening method for cancers, and the other would be to determine the biologic compounds the dogs detect and then design cancer-screening tests based on those compounds."
BioScentDx plans to use canine scent detection to develop a non-invasive way of screening for cancer and other life-threatening diseases. As a next step, the company launched a breast cancer study in November in which participants donate samples of their breath for screening by trained cancer-sniffing dogs. The researchers also plan to separate the samples into their chemical components and present these to the dogs to isolate the substances causing the odour that the dogs detect.
Canines are able to differentiate between serum samples taken from cancer patients and samples taken from normal controls. This study further supports the use of dogs as biomedical research tools for detection of cancer biomarkers. In particular, this study was designed to determine the accuracy of canines’ ability to detect, by scent alone, lung cancer biomarkers in blood serum.
Operant conditioning was used in the form of clicker training to train four beagles to distinguish, by scent alone, blood serum from malignant lung cancer patients when presented along with healthy controls in a double-blind format. Non-small cell lung cancer and healthy control blood serum samples were presented to 2-year-old beagles.
Three dogs were able to correctly identify the cancer samples with a sensitivity of 96.7%, specificity of 97.5%, positive predictive value (PPV) of 90.6% and negative predictive value (NPV) of 99.2%. One of the dogs, Snuggles, was unmotivated to perform during training and tested with 80% specificity and 60% sensitivity. This study paves the way for a larger scale research project designed to explore the use of canine scent detection as a tool for detecting cancer biomarkers, ultimately leading to their identification.
Heather Junqueira, Thomas Quinn, Roger Biringer, Mohamed Hussein, Courtney Smeriglio, Luisa Barrueto, Jordan Finizio, Michelle Huang
[link url="https://www.sciencedaily.com/releases/2019/04/190408114304.htm"]Experimental Biology material[/link]
[link url="https://www.fasebj.org/doi/10.1096/fasebj.2019.33.1_supplement.635.10"]FASEB Journal abstract[/link]