A nose for malice: Similar to dogs, ants can also identify cancer cells by smell, researchers have shown through experiments. After a short training phase, the insects are even able to distinguish between different forms of cancer. Due to their simplicity and the rapid training success, they could represent an alternative to the more complex use of dogs in cancer diagnostics, say the researchers. However, this potential now needs to be explored further.
Early detection is very important: In cancer medicine, diagnostics are of great importance. However, the procedures for evaluating tissue samples are comparatively complex and expensive, which is why alternative methods are always welcome. Researchers have been trying for some time to use the abilities of animals to do this – specifically: their sense of smell. Dogs have already impressively demonstrated that their fine noses can distinguish between cancer cells and healthy tissue. This is because degenerated cells release special volatile substances that the animal’s highly sensitive sensory system can detect. Dogs can even tell certain forms of cancer by smelling bodily fluids.
Six-legged snoops instead of four-legged ones?
However, the use of dogs has a catch: In order for the animals to be able to serve as diagnosticians, they have to be trained intensively. This is costly and time-consuming, which significantly limits the potential of the concept. That is why the scientists led by Baptiste Piqueret from the Sorbonne University in Paris Nord have now turned to animals as possible alternatives that initially seem strange: ants. However, as the researchers explain, it was already known that these insects also have, at least fundamentally, the crucial abilities that dogs also have: ants have a highly sensitive sense of smell and are also able to learn quickly.
The team has now explored the extent to which the crawlers can also sniff out cancer in ants of the species Formica fusca, which is widespread in Central Europe and can easily be kept and reproduced in artificial systems. The researchers produced different olfactory samples for the experiments. For this purpose, laboratory cultures of different types of cancer cells and healthy reference cells were transformed into sample material. The test animals were calibrated to the cancer samples by adding a sugar solution to them.
As it turned out, within a very short training phase, the ants developed a particular liking for the olfactory characteristics of the cancer samples: when they were then given the choice between cancer cell solutions and the equally sweet control cell solutions, they ran straight to the samples they had previously encountered with the special smell pattern. As further experiments showed, the insects can even distinguish between different forms of cancer. The researchers trained the ants to recognize two types of breast cancer, which lead to different courses in patients. In this case, too, the experiments showed that the insects can detect the subtle differences in the smell of the different cell types. As the researchers explain, the abilities of ants, like those of dogs, are based on the ability to perceive cancer-specific patterns of certain volatile substances. As part of the study, they were also able to detect these substances using gas chromatography/mass spectrometry.
Potential for diagnostics
“Our results suggest that ants are useful living tools for detecting biomarkers of human cancer,” the researchers write. In particular, they emphasize that the insects are easy to breed and do not require months of training and time-consuming care like dogs. “Our approach could also be extended to a range of other complex odor detection tasks, such as detecting narcotics, explosives, spoiled food or other diseases such as malaria infections or diabetes,” the team writes.
However, it will probably be some time before ants find their way into diagnostic laboratories, because the concept is in an early development phase: the effectiveness of this method must first be examined more closely. “Our research will now aim to expand the spectrum of cancer-related odors that can be detected by ants,” the researchers write. They also want to find out to what extent the insects can also detect clues in smells that are emitted directly by the body.