Clonally transmissible cancers are somatic cell lineages that are spread between individuals via the transfer of living cancer cells. There are only three known naturally occurring transmissible cancers, and these affect dogs, soft-shell clams, and Tasmanian devils, respectively. The Tasmanian devil transmissible facial cancer was first observed in 1996, and is threatening its host species with extinction. Until now, this disease has been consistently associated with a single aneuploid cancer cell lineage that we refer to as DFT1. Here we describe a second transmissible cancer, DFT2, in five devils located in southern Tasmania in 2014 and 2015. DFT2 causes facial tumors that are grossly indistinguishable but histologically distinct from those caused by DFT1. DFT2 bears no detectable cytogenetic similarity to DFT1 and carries a Y chromosome, which contrasts with the female origin of DFT1. DFT2 shows different alleles to both its hosts and DFT1 at microsatellite, structural variant, and major histocompatibility complex (MHC) loci, confirming that it is a second cancer that can be transmitted between devils as an allogeneic, MHC-discordant graft. These findings indicate that Tasmanian devils have spawned at least two distinct transmissible cancer lineages and suggest that transmissible cancers may arise more frequently in nature than previously considered. The discovery of DFT2 presents important challenges for the conservation of Tasmanian devils and raises the possibility that this species is particularly prone to the emergence of transmissible cancers. More generally, our findings highlight the potential for cancer cells to depart from their hosts and become dangerous transmissible pathogens.

Item Type:	Refereed Article
Keywords:	Tasmanian devil, Tasmanian devil facial tumor disease, contagious cancer, transmissible cancer
Research Division:	Biomedical and Clinical Sciences
Research Group:	Immunology
Research Field:	Cellular immunology
Objective Division:	Health
Objective Group:	Clinical health
Objective Field:	Clinical health not elsewhere classified
UTAS Author:	Pye, RJ (Ms Ruth Pye)
UTAS Author:	Tovar, C (Dr Cesar Tovar Lopez)
UTAS Author:	Darby, J (Ms Jocelyn Darby)
UTAS Author:	Kreiss, A (Dr Alexandre Kreiss)
UTAS Author:	Lyons, AB (Associate Professor Bruce Lyons)
UTAS Author:	Woods, GM (Professor Gregory Woods)
ID Code:	105519
Year Published:	2015
Web of Science® Times Cited:	138
Deposited By:	Menzies Institute for Medical Research
Deposited On:	2016-01-06
Last Modified:	2017-11-07
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