The science. Cancer sniffs ants

A legendary organizer, the ant also has medical talents that are hard to imagine. French researchers first taught these insects to detect cancer in humans. Thanks to their highly developed sense of smell, ants can distinguish healthy cells from diseased ones and even distinguish between different types of cancer.

An ant is more efficient and cheaper than a dog

Some cancers actually release volatile organic compounds (VOCs) that cannot be detected in our nostrils but serve as biomarkers for cancer diagnosis. The group, bringing together scientists from the Sorbonne-Paris-North University, CNRS, the Curie Institute and Inserm, highlighted the effectiveness in this area of ​​a special category of these bugs called Formica fusca, a European species very common and widespread in the north. hemisphere. In the study, published on February 21, 2022 in the journal (1), the main author is Baptiste Piquere, a young doctoral research fellow in the Laboratory of Experimental and Comparative Ethology at the Sorbonne-Paris-Sever University. year on “olfactory detection of human cancer by ants”.

The use of animal skills in medicine is not new. In particular, the Curie Institute is testing dogs’ sense of smell for early detection of breast cancer. But this method is long – from six months to a year of study – and expensive. Ants are faster, cheaper and very efficient. A few tens of minutes are enough to teach them to recognize the smell of cancer cells by presenting them with stimuli only once. And their long-term memory resists extinction in the colony and adapts to unstable conditions.

To conduct the experiment, the scientists created so-called associative learning protocols, in which smell is linked to the reward system. “We put our ant in the center of the arena with the smell of cages in a tube and sugar water nearby, Baptist explains picket. The ant explores the environment and quickly finds a reward to drink. During this time, she will sniff (with her antennae) and understand that the reward is next to this or that smell. » The connection is established: if she is hungry, she must go for this flavor. “It’s a bit of the same principle as when you’re outside and you smell chocolate pain coming from a bakery, the researcher continues. If you are hungry, you will enter the store. »

Lots of olfactory receptors

The researchers started by running tests on 36 ants trained in the process. Then they were presented with two different smells: new and the smell of cancer cells. Result: The ants were almost certainly able to find those associated with the reward. One hundred Formica fusca ants have also learned to detect three cancer cell lines: ovarian cancer and two types of breast cancer. In 95% of cases, insects were able to detect diseased cells.

How to explain the behavior of these small arthropods (referring to the articulated feet or legs)? Their success is due to a particularly sensitive sense of smell due to the large number of olfactory receptors, as well as advanced chemical communication, which allows them to recognize each other after establishing contact with their antennae. The genetic material of ants gives them the best sense of smell among insects. They would have four to five times more olfactory receptors sensitive to odors than most other insects. The two families of ants that have been sequenced will have 377 and 407 odor protein genes compared to 174 bee genes, 74 to 158 mosquito genes and 61 fruit fly genes!

Ants have four to five times more olfactory odor receptors than most other insects.

This first study shows the potential of ants. But, before finding it in hospitals, it is still necessary to evaluate the effectiveness of this method by clinical trials on the human body. Of course, ants would not walk on the bodies of the sick. You can use, for example, urine, saliva or sweat of a person who has the potential to have cancer. Baptiste Piquere says . There will be no direct contact between our ants and patients.»

public health issue

While experiments with the urine of cancer mice continue in the laboratory. If they are definitive, this would be a minimally invasive and inexpensive alternative to detection methods such as MRI or mammography. Early diagnosis of cancer remains a public health problem. This increases the chances of recovery, reduces the severity of treatment, and limits the consequences. In France, the total number of new cases in 2018 was estimated at 382,000. .

And worldwide, cancer is the second leading cause of death after cardiovascular disease, claiming nearly 10 million lives each year. The earlier the disease is diagnosed, the higher the chances of survival. Moral of this study: if “ant does not lend”as Jean de La Fontaine wrote, but it can be very useful.

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