Tumour breakthrough could save tassie devils
Saturday, January 02 2010 @ 08:20 PM EST
Contributed by: jkr
By Felicity Ogilvie for AM
Fri. January 1, 2010 11:20am AEDT
Cancer attacking nerve cells: Scientists have hailed the discovery as a major breakthrough (AAP: Tracey Nearmy)A team of international scientists has made a major breakthrough in the fight to save tasmanian devils from extinction.
The team says it has worked out exactly what kind of cancer is killing the animals, finding that the deadly facial tumour disease is growing in the devils' nerve cells.
Until now, the contagious cancer has been as mysterious as it is deadly.
The scientists have published their findings in today's edition of the journal Science.
Professor Greg Woods, who works at the Menzies Research Unit in Hobart, made the discovery along with colleagues in New York and Melbourne.
"Basically we did some genetic analysis to discover that the tumour is actually about the peripheral nerve cell, called the Schwann cell," he said.
Doctor Tony Papenfuss from Melbourne's Walter and Eliza Hall Institute has identified the genetic signature of the tumour.
"We looked at biological data from biopsies and determined which genes were switched on in the tumours," he said.
"From that we identified a genetic signature of the tumour. When we compared this genetic signature to other normal tissue, we found that it was most like cells called Schwann cells."
Schwann cells keep the nervous system running, and tasmanian devils have a lot of nerves near their whiskers.
Professor Woods says that is why the cancer is attacking the animals' faces.
"The other interesting thing about Schwann cells or nerve cells is that they don't want to produce an immune response against our nerves, otherwise we'd all collapse," he said.
"So that is another explanation as to why the tumour is transmitted, because it's not seen by the immune system. Otherwise, every time we got an infection, we'd have reactions against our nerves."
'Critical first step'
The rare contagious cancer has been spreading across Tasmania for the past 13 years. No-one knows how the disease started.
But Professor Woods says the discovery that the cancer is in the devil's nerve cells suggests the disease has spread from just one animal.
"That's what we're predicting, that at one stage somewhere in the north-east of Tasmania, in Mt William, a devil developed a Schwann cell tumour and as each one cell mutated and started to grow," he said.
"Because of the lack of genetic diversity, it could be transmitted between other devils."
The discovery that the tumour is in the devils' nerve cells will not stop the disease from spreading. But Dr Papenfull says it has ended years of debate about what kind of cancer the devils are catching.
"So for an individual devil, it's got this cancer at the moment, it doesn't mean that much because we still don't have any kind of treatment," he said.
"But in terms of learning more about the biology of the tumour and perhaps in the much longer term indentifying or discovering treatment, this is really a critical first step."
The scientists are now trying to find a vaccine to protect the devils from the cancer.