By VERONIQUE GREENWOOD
Cancer cells, though they don’t alter human metabolism overall, can have altered metabolisms themselves. That means the substances they release could differ from those generated by healthy cells. This idea has been around for decades, but only very recently have biochemical and sensor technology advanced to the point where we can develop portable, hand-held sniffing machines.
Electronic noses have the potential to detect even very small amounts of molecules — but they need to be programmed to look for specific signs wafting up from patient samples. ...
A work in progress, the electronic nose is, for now, an example of how modern medicine can look for answers in unusual places. The impetus that finally pushed Preti and his team to seriously investigate the possibility of cancer detection by smell traces its roots to a dog. In 1989, a letter published in The Lancet reported that a woman had come into the doctor’s office to have a mole looked at. She hadn’t noticed it until her collie-Doberman mix began to sniff the spot intently — even through her pants — and tried to bite it off when she wore shorts. The mole turned out to be an early-stage malignant melanoma, inspiring researchers to test whether dogs, whose smell machinery is at least 10,000 times as sensitive as ours, can tell healthy samples from cancerous ones.
The results from the dog tests have been inconclusive, but to Preti, who has mulled the idea that hidden cancers could be detected from smell molecules since the 1970s, they suggested that there was a real possibility for a new diagnostic. “We think that they’re present very early in the carcinoma process,” Preti said of the scents. “The main question is: Can we be as sensitive as the dogs in picking these things up?”