Ecology and evolution of transmissible cancers PI : Frédéric THOMAS
Collaborators: Beata Ujvari (Deakin University, Australia), Rodrigo Hamede (University of Tasmania), Benjamin Roche (MIVEGEC Montpellier), Nicolas Bierne (ISEM, Montpellier), Christine Destoumieux-Garzon (Université de Montpellier), Guillaume Charrière (Université de Montpellier)
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Transmissible cancers are one of the most intriguing and unexplored host-pathogen systems. The pathogen is a clonal infectious malignant cell line, a rogue cell type that has derived and deviated directly from the host or from a closely related species. While the ultimate fate of malignant cells is usually to expire with the death of the host, evolutionary theory postulates that cancer cell lineages that are able to become transmissible (hence escape the demise of their host) will acquire higher fitness, and consequently be favoured by selection. Once the neoplastic process has crossed the threshold of contagiousness, malignant cells become new parasitic “species”. Currently, eight transmissible cancers (one lineage in dogs, two lineages in Tasmanian devils, and five lineages in four bivalve species), have been recorded in the wild, but their real abundance has most likely been underestimated. Transmissible cancers are a rare type of natural enemy but their ecological consequences can be major (e.g. > 85% population decline in 20 years in Tasmanian devils; epizootic outbreaks in marine mollusk populations). Altogether, the increasing number of case reports is raising major questions: Why do transmissible cancers emerge? How do they evolve? What are their ecological and evolutionary impacts and how to manage them? In this proposal, we wish to address these questions by exploring two contrasted and complementary host/transmissible cancer associations (i.e. vertebrate/invertebrate hosts, presence/absence of motile infective stages, different levels of host specificity) through a multidisciplinary approach.
Project funding: ANR TRANSCAN (ANR-18-CE35-0009) 2019-2023
[Photo credit: Fred THOMAS]
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