Tasmanian devil cancer DFTD
Tasmanian devil cancer research down a blind alley?
Scientists have been investigating a deadly disease afflicting the Tasmanian devil, a carnivorous marsupial on the verge of extinction due to what is called devil facial tumour disease or DFTD. They have followed a single research pathway, assuming the cancer is an allograft, namely a transmissible tumour. For a decade, investigations into possible alternative explanations for DFTD have been neglected, despite calls for transmission studies.
Recent publications:
Josephine Warren and Brian Martin, 17 November 2014, 'What's killing the Tassie devils if it isn't a contagious cancer' The Conversation
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Josephine Warren, 28 April 2016 'When undone science stifles innovation: the case of the Tasmanian devil cancer' Prometheus
Josephine Warren and Brian Martin, 1 August 2018 'Researching new diseases: assumptions and trajectories' Research Innovations and Outcomes
Recently, anomalies in the allograft theory have emerged. The first was in a paper published by Pye et al in 2016 which found tumours in 5 male devils that, although they were "grossly indistinguishable" from the other devil tumours examined, had " no detectable cryogenic similarity" to them and carried a Y chromosome. This contradicted the original hypothesis in Nature that was based on all tumour cells isolated from affected devils being identical and the sex chromosome missing. The authors, part of the Save The Devil Program (STDP), explained this anomaly by adjusting the theory for two distinct transmissible cancers, DFT1 and DFT2.
The second also published in 2016 was a paper by Cui et al in the journal Chemical and Biophysical Research Communications, that, contrary to the allograft hypothesis, which assumed all tumours originated in, and were transmitted from, one female devil, DFTD tumours in male devils had male chromosomes and originated in their hosts. Referring to the Pye et al. study, Cui et al concluded: the cytogenetic results showed that all the DFTD2 tumours containing a Y chro- mosome were from five male devils (isolated in 2014 and 2015) whereas all the DFTD1 tumours from four female devils (isolated in 2015) did not contain a Y chromosome, clearly indicating that all the DFTD tumours isolated in 2014 and 2015 were induced in their own hosts. (Cui et al 2016).