Cancer diagnosis is frightening, invasive, time-consuming, and expensive. In the United States, more than 1.6 millions are diagnosed with cancer each year. That’s a lot of biopsies and a lot of looking at cells under highly sensitive microscopes.
. What if cancer detection was as easy as taking a whiff of the samples?
We know that some animals like mice and dogs have sensitive noses that are able to detect disease. French scientists were inspired by these studies to investigate whether ants, a smaller creature that is well-known for its olfactory abilities, could be able to do the same.
“Using olfaction to detect diseases is not a novel idea,” says Baptiste Piqueret, PhD, a researcher at Sorbonne Paris Nord University and lead author of the study. “Knowing how well ants can learn and how they use olfaction, we tested the abilities of ants to learn and detect diseases.”
While this is still far away from real-life clinical use, it could one day lead to a cheaper, more accessible alternative for detecting cancer. How would this new diagnostic method look?
Cancer cells make volatile organic compounds (VOCs) – organic chemicals that smell and can serve as biomarkers for diagnosis.
To train the ants how to identify VOCs, researchers placed breast-cancer and healthy cells in a dish. However, the cancer cells were given a sweet treat.
“We linked a reward to cancer’s smell,” Piqueret said.
This is a technique called classical or Pavlovian conditioning. A second stimulus (food), is used to stimulate a behavior. After repeating this process several times, the ant will learn that the first stimulus predicts which one it will receive. It will then seek out the odor in order to find food.
After the training was completed, researchers presented the ant both the learned odor as well as a new one, this time without any reward. The new odor was more popular with the ants than the learned one.
” If you feel hungry and smell fresh bread, you’ll go to the nearest bakery.” Piqueret says. “This is the same mechanism the ants are using, as you learned that fresh bread odor equals food.”
Dogs can detect VOCs using the same technique but take months and hundreds of trials to condition, the researchers note. F. fusca ants learn fast, requiring only three training trials.
Ants communicate primarily through scent, and this sophisticated “language” makes them very sensitive to odors.
“Since ants are already well-attuned to detecting different chemicals, this makes them ideal for scent recognition,” says Corrie Moreau, PhD, an evolutionary biologist and entomologist at Cornell University.
In their tiny ant worlds the little creatures use chemical pheromones (chemicals called pheromones) to communicate information to their nest members.
“There are alarm pheromones to signal an intruder, trail pheromones so an ant knows which way to walk to a food source, and colony-level odors that signal another ant is a member of the same colony,” Moreau says.
But closer inspection will reveal that an ant’s nose is not visible. Their antennas “smell” the ant.
“These specialized structures are covered with highly sensitive receptors to be able to discern even small chemical differences,” says Moreau.
There are over 14,000 species of ants, and as far as scientists like Moreau know, a