You probably won’t see them at a hospital or doctor’s office anytime soon, but silky ants (Formica fusca) could someday provide a rapid and inexpensive way to test for cancer, thanks to their incredible sense of smell. The ants could potentially save lives through early detection and help patients avoid invasive and often painful testing methods such as biopsies.
In a recent study, scientists successfully harnessed the ants’ powerful olfactory systems – specifically the antennae on their heads – to differentiate between cancerous and non-cancerous cells.
A team of researchers led by Baptiste Piqueret of the Max Planck Institute for Chemical Ecology trained 35 silky ants to associate the volatile organic compounds (VOCs) released by tumor cells with a sweet reward. The study did not directly involve human patients – instead, tissue from breast cancer tumors was grafted onto mice, whose urine was then used to train the ants. It took just three short training sessions for the ants to learn the difference between urine from healthy mice and urine from mice with cancerous tumors.
After their training, the ants were placed in a petri dish, where they spent an average of 20% more time near the urine of mice with cancer than that of the cancer-free mice, as they had come to associate the smell with a sugary reward.
Although the results are very promising, many questions remain before the ants can truly become a diagnostic tool. The next step will be to perform a similar experiment using urine from humans. One important issue to resolve is whether the ants would be able to detect a wide range of cancerous cells if they were only trained on one type of cancer (e.g. breast cancer, as in this study).
Antennae to the rescue:
- Another consideration is that humans are far more heterogeneous than mice. As a result, our urine samples would have a wider range of odors influenced by factors such as age, sex, and diet.
- Previous studies have already provided evidence that ants aren’t the only animals that can detect the smell of cancer. Dogs, roundworms, and fruit flies have successfully identified VOCs from tumor cells, though ants are likely to be the easiest and least expensive to train.
- Because ants don’t have noses, they use the antennae on their heads to detect odors. Antennae are also used to release chemical cues for communication among members of their colony, including finding food and protecting their young.
