These little worms are drawn to cancer, and that’s great news

C. elegans is anything but photogenic, but it has opened up sensational avenues of research in the fight against cancer.

Humans have known for centuries that the legendary truffle of our dog friends is a tool of formidable efficiency. But in recent years, several studies have highlighted other remarkable features; we now know that a sufficiently trained dog can, for example, detect certain forms of cancer just by smell. So the idea has been explored with other species… and it also works with small worms.

This is indeed the subject of an astonishing publication relayed by EurekaAlert, the scientific watch and popularization body of the prestigious Science group. The text, titled “Worm we have chip” (“Worm on a chip”), highlights the ability of a well-known nematode to identify lung cancer; researchers have based themselves on this concept to offer a test that is both precise and easy to use.

A worm with dog

Behind the barbaric name of this worm, baptized Caenorhabditis elegans, hides a true star of science; although hardly photogenic, this little beast is a top model organism. In particular, it has played a fundamental role in genetics and the science of human development, since we share approximately 35% of our genes.

It suffices to visit the academic search engine Google Scholar to find that there are more than 1,140,000 research papers referring to it, which is colossal; for comparison, even the term “carbon”, which covers absolutely all fields of science, appears “only” 5,690,000 times. And it’s not just a façade of notoriety.

C.elegans has supported some of the most important works in the history of biology. Among them, there are even five papers that have won Nobel Prizes for their respective authors. Cherry on the cake, C.elegans even contributed to work absolutely essential to our current understanding of cancer, in a totally different context. This shows the importance of this worm, which is not very large.

A “worm on chip”

It is common knowledge among researchers that this nematode is particularly sensitive to odors; some attract it, while others repel it. That’s when a team had a brilliant idea: what if C.elegans was sensitive to certain cancer cells, as is the case with man’s best friend? Quickly, several results suggested that it could be a real lead.

Based on these elements, Korean researchers have mounted their own study. Their objective: to move on to the concrete phase with a simple test, usable in real conditions. They took tissue samples, some from healthy individuals, and some from cancer patients. They then exposed two groups of nematodes to these samples.

The first group consisted of C.elegans normal. The second, on the other hand, was a control group genetically modified with the aim of depriving them of their olfactory receptors. At the end of the test protocol, they found that the majority of the worms in the first group had crawled in the direction of the cancerous samples. On the other hand, they did not find this difference in worms deprived of their sense of smell.

Their worm-based device therefore behaved like a test for diagnosing cancer, in this case of the lung. An observation that suits researchers well, even if they still can’t explain it. “We don’t know why C. elegans is attracted to cancerous lung tissue, but we imagine these smells must be similar to that of its favorite food.”, they suggest.

Prevention is better than cure

Whatever the reasons, they conducted several rounds of such preliminary tests to confirm the results. They estimated that this method could detect cancer cells in about 70% of cases. This looks very much like an impressive proof of concept. The kind of discovery that could well find clinical applications in the relatively near future.

This is exciting because the detection of cancers is an absolutely essential factor in the management of this disease. The later they are detected, the worse the prognosis. And sometimes very quickly in the case of the most aggressive forms. The fact of being able to detect early and with great precision is therefore a major global public health issue.

Despite this well-identified priority, it remains very difficult to detect these sneaky pathologies. Too often, patients don’t feel the symptoms until it’s too late; tumors have the annoying habit of being able to go unnoticed at the onset of the disease. According to The Cancer Letter, a publication specializing in this pathology, 85% of cancers would go unnoticed during this early sentence. The problem is largely due to the few options available.

Because today, in many cases, a biopsy coupled with a thorough anatomo-pathological examination remains the only way to propose an accurate diagnosis. However, for all the reasons that one can imagine, this invasive method which consists in taking a sample of tissue from a suspected organ lends itself rather poorly to the routine examinations necessary to effectively anticipate the disease…

A very promising track just waiting to be dug

In this context, this score of 70% is already encouraging for a test of this type; but the team believes it has enough leeway to improve accuracy even further. This could in particular involve a form of conditioning, in order to develop the sensitivity of C.elegans at different forms of cancer. Researchers could also achieve this by using genetically modified nematode strains.

Once the precision is sufficient, the team even hopes to adapt its concept to other types of samples. In theory, in addition to tissue, the researchers believe that this technique could be used to analyze samples ofurine, saliva, or even air expired like a simple breathalyzer. It would therefore be a non-invasive test method, with all that this implies for the patient compared to the biopsy.

The purpose is not necessarily to keep a stock of nematodes in each laboratory; Ultimately, it is more a matter of precisely identifying the physiological mechanisms that allow them to track the biological markers of cancer in this way. Ideally, it might even be possible to detect cancer earlier than current methods allow.

This would then allow mass-produce tests that are inexpensive, non-invasive and highly accurate; which considerably improves the overall management of the disease. Such a product would therefore be a small revolution in oncology and public health. But that still goes far beyond the scope of this work, and we will have to be patient.

Fortunately, this team is not the only one working on this issue. We can therefore hope for substantial progress in the relatively near future. After more than a century under the microscope of researchers, C.elegans is decidedly far from having revealed all its secrets to us.

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