Dogs are known to be great at sniffing out cancer, but new research shows tiny worms do very well too - and they’re easier to handle in a lab.
Scientists at Myongji University in South Korea found that roundworms wriggle their way toward cancer cells because they’re attracted to their distinctive smell.
The researchers put together a basic "worm-on-a-chip" device that could someday help doctors diagnose cancer early, noninvasively and more cheaply.
Currently, doctors diagnose lung cancer using imaging tests or biopsies, but these methods typically can’t detect cancerous tumours at their earliest stages when they have a better chance of being treated.
Dogs have already demonstrated the extraordinary skill of sniffing out cancer in human breath, sweat, urine and stools, but trained pups come in short supply and are not the most practical companion in a lab.
Instead, researchers Nari Jang and Shin Sik Choi decided to use C. elegans worms, also known as nematodes, which measure just around 1 mm and also have a heightened sense of smell.
Previous research has shown these worms were attracted to urine from people with various kinds of cancer.
To put the worms to the test, the team designed a chip with a well at each end connected by channels to a central chamber, and placed it in a Petri dish.
They added a drop of liquid containing lung cancer cells at one end, and normal cells at the other, and placed worms in the central chamber.
After an hour, the team observed that more worms had crawled toward the lung cancer cells than the normal cells.
Based on their tests, the researchers estimate the device was about 70 per cent effective at detecting cancer cells.
The findings were presented at a meeting of the American Chemical Society in San Diego, California on Sunday.
Jang and Choi found that the roundworms were attracted to the lung cancer cells because of a volatile organic compound called 2-ethyl-1-hexanol, which has a floral scent.
“We guess that the odours are similar to the scents from their favourite foods,” Jang said.
They now hope to make the test more accurate by previously exposing the worms to cancer cells and thus training them to respond to this floral scent.
Once they perfect this device, the researchers also plan to proceed with testing urine, saliva and human breath and see how the worms fare in detecting other forms of cancer.