A second transmissible cancer in Tasmanian devils

Abstract

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.

Widespread transmission of independent cancer lineages within multiple bivalve species

“…Along with the recent identification of a second independent lineage of transmissible cancer in Tasmanian devils 19 , these findings confirm that under suitable conditions, the development of transmissible cancer can occur multiple times, and suggests that some species may be more susceptible to development of transmissible neoplasia than others.…”

Age-Structured and Vaccination Models of Devil Facial Tumor Disease

“…We recommend breeding Tasmanian devils, vaccinating them, and strategically releasing them in locations with high potential for their survival, such as areas that have had road fencing installed to reduce vehicular death, areas where selective culling is utilized, or areas where multiple conservation techniques are used. Further modeling efforts may consider how vaccination of wild devils may help decrease disease prevalence, how natural resistance such as those devils in the West Pencil Pine location [28] may decrease disease prevalence, and how the second devil facial tumor disease (DFT2) may hurt devil populations further [29].…”

Rapid evolutionary response to a transmissible cancer in Tasmanian devils

“…The magenta lines indicate the approximate location of the disease front67 in 2000, 2005, 2010 and 2015.…”