Integrating exhaled breath diagnostics by disease-sniffing dogs with instrumental laboratory analysis

Abstract

Dogs have been studied for many years as a medical diagnostic tool to detect a pre-clinical disease state by sniffing emissions directly from a human or an in vitro biological sample. Some of the studies report high sensitivity and specificity in blinded case-control studies. However, in these studies it is completely unknown as to which suites of chemicals the dogs detect and how they ultimately interpret this information amidst confounding background odors. Herein, we consider the advantages and challenges of canine olfaction for early (meaningful) detection of cancer, and propose an experimental concept to narrow the molecular signals used by the dog for sample classification to laboratory-based instrumental analysis. This serves two purposes; first, in contrast to dogs, analytical methods could be quickly up-scaled for high throughput sampling. Second, the knowledge gained from identifying probative chemicals could be helpful in learning more about biochemical pathways and disease progression. We focus on exhaled breath aerosol, arguing that the semi-volatile fraction should be given more attention. Ultimately, we conclude that the interaction between dog-based and instrument-based research will be mutually beneficial and accelerate progress towards early detection of cancer by breath analysis.

Can We Use Human Odors to Diagnose Malaria?

“…Over the last decade, biomimetic crossreactive sensor arrays devices have become more sensitive and affordable, and with time invested into method development, could become a practical platform to detect changes in volatile signatures due to malaria. Another possible avenue for the detection of malaria biomarkers involves training dogs to detect malaria-specific human odors, as they have previously been trained to do for odors associated some with some forms of cancer [24]; research into this possibility is currently underway.…”

Breast Cancer Detection From a Urine Sample by Dog Sniffing

“…However, VOCs are affected by physiological factors such as dietary and smoking habits, infections, and benign diseases [40], which GCMS cannot detect all or even nearly all chemicals present [14], nor clarify the exact chemical compounds and/or their combinations. Combining this dog-based study with instrument-based research would be mutually bene cial for further analysis [41].…”

Breast Cancer Detection from a Urine Sample by Dog Sniffing

“…However, VOCs are affected by physiological factors such as dietary and smoking habits, infections, and benign diseases [40], which GCMS cannot detect all or even nearly all chemicals present [14], nor clarify the exact chemical compounds and/or their combinations. Combining this dog-based study with instrument-based research would be mutually beneficial for further analysis [41].…”