Microscopic worms can “smell” lung cancer, and scientists have harnessed this ability to create a potentially life-saving device. The so-called “worm-on-a-chip” could one day be used to detect cancer in its very early stages.
Move over dogs, the roundworm C. elegans is the new cancer-sniffing maestro. The tiny worms, also called nematodes, are attracted to certain odors – including those released by lung cancer cells.
In early-stage research presented yesterday at the American Chemical Society meeting in San Diego, a team reported that the worms prefer to wriggle toward cancerous cells over non-cancerous ones.
“Lung cancer cells produce a different set of odor molecules than normal cells,” Dr Shin Sik Choi, of Myongji University in Korea, said in a statement.
“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.”
Findings suggest the worms are about 70 percent effective at doing just that. The team hopes this can be improved upon by using worms with a “memory” of cancer-specific scents, having been previously exposed to cancer cells.
The chip itself has a well at either end, where lung cancer cells and normal lung cells are placed. The worms are placed in a central chamber and can shuffle down connecting channels. Following their keen “noses”, the majority crawled toward the cancer cells. Those whose ability to smell had been hindered by mutations to the odor receptor gene odr-3 did not exhibit this behavior.
The next step, once the device has been optimized, is to use urine, saliva, or perhaps even exhaled breath, instead of lung cancer cells.
“We will collaborate with medical doctors to find out whether our methods can detect lung cancer in patients at an early stage,” Choi said.
Early diagnosis is crucial for favorable patient outcomes. When cancers are caught early, treatments are more likely to be successful, and survival chances are increased.
Lung cancer patients diagnosed at the earliest stage have a 90 percent chance of surviving for at least a year, compared to just 20 percent for those diagnosed at the most advanced stage. Current diagnostic techniques include x-rays and biopsies, but these often fail to catch lung cancer in its early stages.
Doctors have had to turn to other avenues to screen for lung cancer – by using animals, for example. Dogs make good candidates, having been found to successfully sniff out cancerous cells (although not as well as ants), however, they don’t make the most practical lab fellows.
Worms, on the other hand, are small – only 1 millimeter (0.04 inches) long – easy to grow, and cheap to keep. And, of course, they’re pretty good at identifying cancer cells.
Other studies have suggested they could be attracted to an organic compound called 2-ethyl-1-hexanol, which has a floral scent and is produced by lung cancer cells.
“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,” Nari Jang, a graduate student who is presenting the work, said.
Hurray for hungry worms!