Tasmanian devil cancer cause revealed

Tasmanian Devil relaxing by http://www.waynemclean.com -Wayne McLean. http://en.wikipedia.org/wiki/User:Jgritz

January 2010. The first set of Tasmanian Devils' genetic sequencing has revealed the origin of the unique transmissible cancer now devastating the devil population, offering hope that the rapid decline in devil numbers can be arrested and giving scientists new insights for cancer research.

The work was done by an international team of scientists lead by Dr Elizabeth Murchison, who conducted the research at The Australian National University in the laboratory of Professor Jenny Graves of the ANU Research School of Biology and the ARC Centre of Excellence in Kangaroo Genomics. The team made the breakthrough by studying and comparing the genes active in both healthy and sick Tasmanian Devils.

Advance in detection
Their research reveals that the origin of the cancer is a tumour of a Schwann cell. Schwann cells normally wrap around nerves to insulate them.

The finding offers considerable hope that the cancer can be more rapidly identified and at earlier stages, as one of the Schwann cell proteins gives a clear and distinctive genetic signal that could help distinguish between the facial cancer and other types of cancer on the animal.

Probably originated just 20 years ago
"We found that about 14,000 genes are expressed at a low or high rate in normal tissues, and in the tumour, but their profiles are quite different. We realised the tumour profile was fairly unusual and included genes that made some strange proteins that are highly expressed in Schwann cells. This was a real surprise - I don't think anybody had guessed that," said Professor Graves.

Lack of genetic variation a major problem
"This tells us that the tumour arose from one Schwann cell in one animal in Tasmania probably less than 20 years ago. It was spread to other animals by biting because devils have little genetic variation, so cannot recognise cells from another animal as foreign and reject them.

"Now we have a better idea what we're up against. The good news is that one of the active proteins is easy to detect and it will give us the chance diagnose the cancer early, which is important for setting up cancer-free ‘insurance populations'. It also allows us to study the way the cancer changes over a long period, which potentially offers new insights for all cancer research."

Professor Graves said the research was an essential step in safeguarding the future of the Devils.

60% of devils already dead
"The cancer has devastated Tasmanian Devils," she said. "It eats up their mouths, eyes and they soon die of starvation. It has wiped out around 60 per cent of the world's devils and is likely to lead to their extinction in the wild within 30 to 50 years. It's a uniquely horrible cancer, and it is critical to know about it at the genetic level."

The devil genetic research was a labour of love for Tasmanian-born Dr Murchison, who is now spending two years at the Sanger Institute in the UK. While she was undertaking a postdoc at Cold Spring Harbor Laboratory (USA) she drummed up support for the study. She undertook the analysis of the data with input from bioinformatics experts in Melbourne and wrote the paper, published today in Science, while working as part of Professor Graves' Comparative Genomics Research Group at ANU.