Friday, January 01, 2010

Infectious cancer

The media seem generally to be playing the significance of this down but it would seem to be a warning of what is possible in humans. Cancer is normally a degenerative disease, not an infectious disease

AN international team of scientists has discovered the genetic marker for a deadly cancer ravaging the Tasmanian devil population, and they say their findings pave the way for developing treatments. Researchers analysed tumour cells taken from facial cancers in the animals, the world's largest marsupial carnivores, and found the disease probably starts in Schwann cells - a type of tissue that cushions and protects nerve fibres.

"Our findings represent a big step forward in the race to save the devils from extinction," said Elizabeth Murchison, who works with the US Cold Spring Harbor Laboratory and the Australian National University.

Deadly facial tumour disease (DFTD) has ravaged the wild population. Australia raised protection levels for devils in May and listed them as endangered due to DFTD. DFTD is a unique type of cancer, transmitted from animal to animal via biting or other physical contact, which transfers living cancer cells between individuals. Only two cancers are known to spread in this way - the other is found in dogs. The devils' tumours are mostly found on the face and mouth, but often spread to internal organs.

Writing in the journal Science, the researchers said that, with no diagnostic tests, treatments or vaccines currently available, the disease could wipe out the entire species in 25 to 35 years.

The team's genetic analysis confirmed that tumours spread from animal to animal are genetically identical because they originate from a single line of cells. Using advanced sequencing technology, the team identified the originating cell by comparing the "transcriptome" - the complete set of genes that are turned on in tumour cells -- with a genetic readout of other tissues. The scientists found the tumours' genetic signature best matched that of Schwann cells, but said they were still unclear about how these nervous system cells spawned cancer.

Identifying the genetic marker could help accurately diagnose the disease and help to develop treatments, they said. "Now that we've taken a good look at the tumours' genetic profile, we can start hunting for genes and pathways involved in tumour formation," said Greg Hannon, who worked on the study.

The study will also help scientists distinguish between DFTD and other types of devil cancers, helping them to identify and isolate affected animals and contain the disease's spread.

SOURCE. The journal abstract is here.

More than a third of health workers believe coffee causes cancer despite no evidence of a link, according to a survey

Good to see the WCRF being a bit skeptical this time. They still talk nonsense about diet, though.

Health professionals are less likely to be clued up than the public, with 36 per cent thinking coffee can cause the disease compared with 12 per cent of the general population. The World Cancer Research Fund (WCRF) commissioned the survey of 143 NHS workers, including nurses, health visitors and GPs.

However, health professionals did score highly on knowing that poor diet increases risk of cancer (81 per cent), compared with 63 per cent for the general public. Overall, 79 per cent of workers were aware that being overweight increases the risk of cancer, compared with 60 per cent of the public, and 78 per cent knew of the link with alcohol, compared with 51 per cent of the public.

But the percentage who were aware that not exercising increases the risk of cancer dropped to 64 per cent among NHS workers and 47 per cent of the public.

Silvia Pastorino, health professionals publications manager for the WCRF, said the survey was small but revealed some health workers are still not aware what lifestyle factors increase the risk. She said: "There is no strong evidence that coffee increases the risk of cancer. "In fact, we often suggest drinking unsweetened tea or coffee as an alternative to sugary drinks. "While I am not surprised that many of the general public are not aware of this, it is worrying to think this may also be the case for some health professionals."


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