Studies on canine detection of human cancers have been impressive for lung, breast, melanoma, ovarian, prostate, and colon cancers. It is thought that cancers produce volatile organic compounds that should be subject to detection by canine or lab testing. Accordingly, there has been a tremendous interest in the development of the “electronic nose†(e-nose).
http://www.jwatch.org/na42937/2016/12/01/electronic-nose-detecting-barrett-esophagus
An “Electronic Nose†for Detecting Barrett Esophagus