Scientists from the University of Konstanz, Germany, are the first to demonstrate that fruit flies can distinguish cancerous cells from healthy ones via their sense of smell. The team has genetically modified fruit flies so that their antennae glow when they detect a cancerous odor. In an experiment, scientists directed smells at fruit flies. The fruit flies' appearance was monitored via a microscope.

Cancer cells and normal cells emit slightly different odors due to their metabolic differences. Dogs and bees have both previously been shown to be capable of detecting cancerous cells. The Konstanz research looked at whether fruit flies, with their sensitive sense of smell, could do the same. In finding that this was indeed the case, the research focused on modifying receptor cells on the fruit flies' antennae to glow when a cancerous odor was detected.

Most olfactory receptor neurons have a specific olfactory receptor type, but the receptor neurons of fruit flies have about 50 different types of receptor. Different odors cause a different response in the receptor neurons, and the scientists were able to modify the relevant neurons so that a response triggered by a cancerous odor caused a fluorescent protein therein to glow.

"What really is new and spectacular about this result is the combination of objective, specific and quantifiable laboratory results and the extremely high sensitivity of a living being that cannot be matched by electronic noses or gas chromatography", says Giovanni Galizia, who led the project.

According to the the research, not only were cancer cells able to be told apart from healthy cells, but even different types of cancer cells were able to be differentiated via the fruit flies' antennae. Galizia hopes that the research can be used to accelerate the process of creating devices that can detect cancer quickly and non-invasively.

"The high sensitivity of the natural olfactory receptors, paired with the quickness with which we can generate these test results, might lead to the development of a cheap, fast and highly-efficient pre-screening that can detect cancer cells well before we can discover them with the present diagnostic imaging techniques," he explains.