Finding Cancer: Ants Versus Dogs

DO YOU KNOW THE FILM ALIEN VERSUS PREDATORS? Today, I want to put ants up against dogs, at least for detecting cancer in humans. We explore an extraordinary new proof-of-concept study from French researchers suggesting that ants may be a new player in the game.

You may already know about the smell-sensing abilities of dogs. But dogs are not the champion in the sniffing arena. Smithsonian Magazine describes this animal as a walking dictionary of odors. Do you know to what animal it refers?

If you guessed the elephant, you are correct. Writing in Smithsonian Magazine, Paul Waggoner, associate director of the Canine Detection Research Institute at Auburn University, adds that rats and mice smell at least as well as dogs, and jackals are uncanny.

But for attitude? Your German shepherd prevails over those other animals. The problem? Training and keeping a detection dog is challenging and not cheap. Researchers are turning to mice, locusts, honeybees, and other animals in this context.

Cancer detection — Enter the ant

“Am I as admirable as that ant?”
― Nobuyuki Fukumoto, Saikyō Densetsu Kurosawa 11

Having been blessed to have studied with the late pioneer of evolutionary biology, E.O. Wilson, and his colleague Bert Hölldobler, I am fascinated with ants.

As a doctor specializing in cancer, you can imagine my delight at seeing this headline: “Cancer-sniffing ants prove as accurate as dogs in detecting disease.”

Scientists in France have shown they can rapidly train a specific ant species to detect cancer cells. Moreover, the accuracy of the insects is equivalent to that seen in other bio-detection heroes, including dogs.

The new study examines the ant species Formica fusca. Could these ants be trained? The researchers already knew that ants can home in on particular volatile organic compounds (VOCs) and that certain cancer types are identifiable by their unique VOCs.

Can these two observations be combined? In other words, can ants be trained to detect cancer cells?

In as few as three training trials, the ants learned to differentiate between cancer and non-cancer cells with an accuracy similar to that seen in dog studies.

The researchers concluded:

“Formica fusca ants can detect the VOCs emitted by cancer cells. A conditioning protocol based on only three training trials was sufficient for ants to associate cell-derived VOCs with a reward. Ants were able to i) perceive the presence of cells in a medium, ii) differentiate cancerous VOCs from non-cancerous ones, and iii) differentiate between two cancerous samples based on VOCs.”

The ants appear to be as good at detecting cancer as their canine counterparts. However, ants require only 30 minutes of training (over a training time of about three days), while dogs generally take 6 to 12 months.

Remarkably, the ants could distinguish between two different forms of breast cancer: The most favorable form (Luminal A)and a more aggressive one (“triple-negative”), respectively.

The researchers, referencing historical ant training investigations, believe that individual ants can be used to detect cancer cells up to nine times before their conditioned responses begin to wane.

This study is proof of concept, as numerous problems would need to be solved before ants can help detect cancer in the real world. Still, I am delighted that ants have demonstrated one more remarkable ability.