Move over dogs, ants are the new olfactory superheroes. A new study has found that ants can “sniff out” cancer tumors in urine samples.
The study, published in the journal Proceedings of the Royal Society B, found that ants’ sense of smell is so strong that they can detect cancer in urine with very little training.
“Ants can be used as bio-detectors to discriminate healthy individuals from tumor-bearing ones,” study author Professor Patrizia d’Ettorre, of Sorbonne Paris Nord University, said, Sky News reported. “They are easy to train, learn fast, are very efficient, and are not expensive to keep.”
For the study, the research team used 70 ants (species Formica fusca) and exposed them to urine samples of mice with, and without, tumors.
The mice were transplanted with human breast cancer tumors, using a technique called xenografting. The experiment was quite simple actually. Urine from both cancer-afflicted and healthy mice was collected. The ants were trained by placing a drop of sugar water in front of the urine from rodents having cancer. When the sugar water was removed, the insects hung around cancer urine for about 20% longer than that of healthy mice, the study found. This is textbook association learning. The ants were made to associate the smell of tumors with a sweet reward.
“We trained them with associative learning to associate a given odor – cancer – with a reward and, after very few trials, they learned the association,” Prof d’Ettorre explained. “We demonstrated that ants can discriminate the urine of healthy mice from the urine of tumor-bearing mice.
Unbelievably, it took just three rounds of training, around 10 minutes total, to teach the ants smell association. For context, training cancer-smelling dogs can take around six months.
“That’s something we were not expecting, to see it that fast,” Baptiste Piqueret, an ethologist at Sorbonne Paris North University and lead author of the study said, as per Scientific American.
The research team has previously shown that the same species of ants could differentiate between cancer cells and healthy cells grown in culture.
However, this time the researchers leveled up by trying the experiment on urine samples. “This is more similar to a real-life situation than using cultured cancer cells,” Prof d’Ettorre noted. “We were surprised by how efficient and reliable the ants are.”
Now, the research team wants to investigate the minimum size of tumors that can be detected by the ants. In the new study, the tumors were proportionally large for mice. In the future, scientists hope to mimic the same results for human urine.