Researchers have proposed a dirt-cheap diagnostic tool to sniff out cancer: lab worms, a seemingly more practical alternative to disease-detecting dogs.

Canines’ incredible sense of smell has shown their ability to smell disease in humans, including cancer and the coronavirus, with accuracy outpacing some of the best oncological research has to offer.

But even a very good “doctor dog” can only do so much, leading researchers at Myongji University in Korea to seek a better solution.

Researchers at the institution’s College of Natural Science found that microscopic roundworms — specifically, a soil-dweller called a nematode that measures no more than a millimeter in length — can sense the odor molecules of lung cancer just as dogs do, and at a much lower cost.

The results of successful “worm-on-a-chip” experiments are being presented at the American Chemical Society (ACS) Spring 2022 meeting this week through March 24.

“Lung cancer cells produce a different set of odor molecules than normal cells,” said Shin Sik Choi, the project’s principal investigator, in an ACS news release. “It’s well known that the soil-dwelling nematode, C. elegans, is attracted or repelled by certain odors, so we came up with an idea that the roundworm could be used to detect lung cancer.”

Previous trials involving nematodes in petri dish environments showed the worms were drawn to the urine of cancer patients as opposed to those without the disease. Choi, with credit to graduate student researcher Nari Jang, devised a simpler application for worm-based diagnostics: worm-on-a-chip.

The tiny chip was constructed out of a tiny plastic polymer and designed with a pool in the middle — the worm chamber — and a well leading out either end of the rectangular surface. A sample of lung cancer cells was dropped into one side of the well, while normal lung cells were placed at the other.

Researchers waited for an hour to find that more nematodes had shimmied toward the lung cancer cells as opposed to healthy ones.

Overall, their worm-on-a-chip device boasted an accuracy rate of about 70%, and there could be ways to make their test even more accurate and efficient and apply it to other forms of cancer.

“We will collaborate with medical doctors to find out whether our methods can detect lung cancer in patients at an early stage,” Choi concluded in his comments, which also acknowledged the support and funding of the National Research Foundation of Korea.

Their study also found that nematodes have a taste for a type of alcohol compound that produces floral fragrance. “We don’t know why C. elegans are attracted to lung cancer tissues or 2-ethyl-1-hexanol, but we guess that the odors are similar to the scents from their favorite foods,” added Jang.