Love research breakthroughs? Then love this worm
Scientists in Japan have just published new work suggesting that tiny worms could ‘sniff out’ cancer as a diagnostic test for patients. This may sound surprising, but in terms of cancer research breakthroughs, the humble worm is already punching way above its (very small) weight.
At just 1 mm long and completely transparent, 10,000 C.elegans worms fit into a petri dish with room to spare. Which is one reason why these worms might ultimately make good 'sniffer dogs' for cancer. In this latest study the researchers were able to show that C.elegans were attracted to cancer samples from patients and urine from cancer patients, but avoided urine from healthy patients. And although unable to detect specific types of cancer, the researchers suggest these worms could become a quick, cheap, and painless part of cancer diagnostic tests.
Whether sniffer worms are the future remains to be seen. But what we do know is that regardless of what happens next, C.elegans have already single-handedly changed what we know about cancer at the most fundamental level.
What’s in a worm?
But why study these worms in the first place? Many reasons. Being able to see right through to their internal workings certainly makes things easier. And they grow quickly, becoming 'elderly' by 2 weeks old. Plus they are easy to keep - liking nothing better than to munch on a bed of bacteria, preferably E.coli.
Yet despite their simplicity, the worm has a surprisingly similar internal structure to us, including a digestive system (stained green in the picture above), nervous system, and muscles. This similarity continues down to the cellular level, and even further down to the level of our genes.
We share roughly 40 per cent of our DNA with C.elegans, and the processes which regulate how our cells grow, divide, grow some more, divide again, and so on, are strikingly similar in both worm and human. Plus we both have very similar versions of major cancer genes, like p53, for example.
But with just 959 cells to its name (compared to a recently estimated 37.2 trillion of our own cells ) and each and every one lovingly catalogued by the scientists who study them, we already know much more about the basic processes that drive C.elegans than we do ourselves.
All this begins to explain why these worms have become a darling of the cancer research field. And how they have helped scientists make discovery after discovery, telling us how cancer begins, develops and spreads.
From understanding how and why cells divide, to figuring out why cancer cells don’t die, C.elegans has told us so much about the basic building blocks of cancer. Worm studies have helped shed light on how DNA damage and mutations can lead to cells becoming cancerous, and worms have helped scientists make sense of cancer metastasis, that is, how tumour cells can spread and invade other parts of the body.
The importance of these discoveries is underlined by the fact that an early champion of C.elegans, Sir John Sulston, and his fellow worm pioneers went on to win the 2002 Nobel Prize in Physiology and Medicine. Their groundbreaking work helped us begin to understand how our genes control the behavior of our cells - a major process we need to know more about to get to the bottom of cancer.
But even John Sulston admits that there is still so much more the worm can tell us. "If we understand the worm, we understand life," he has said. "Which of course we're nowhere near."
And this is why we’re funding cancer researchers like Professor van den Heuvel in the Netherlands. He is studying a group of C.elegans genes called SWI/SNF genes with the aim of finding out how damage to this relatively unknown group of genes can lead to cancer. Ultimately, he wants to identify ways to stop potentially cancerous cells dividing when SWI/SNF genes fail, and to test any new approach in human cancer cells that have lost SWI/SNF gene activity.
So with this in mind we all hail to the mighty tiny worm, and look forward to yet more new discoveries.
Many thanks to Professor van den Heuvel for his microscope picture of a C.elegans worm used above.