Cancer in wildlife: patterns of emergence

Abstract

Cancer is ubiquitous in wildlife, affecting animals from bivalves to pachyderms and cetaceans. Reports of increasing frequency demonstrate that neoplasia is associated with substantial mortality in wildlife species. Anthropogenic activities and global weather changes are shaping new geographical limitations for many species, and alterations in living niches are associated with visible examples of genetic bottlenecks, toxin exposures, oncogenic pathogens, stress and immunosuppression, which can all contribute to cancers in wild species. Nations that devote resources to monitoring the health of wildlife often do so for human-centric reasons, including for the prediction of the potential for zoonotic disease, shared contaminants, chemicals and medications, and for observing the effect of exposure from crowding and loss of habitat. Given the increasing human footprint on land and in the sea, wildlife conservation should also become a more important motivating factor. Greater attention to the patterns of the emergence of wildlife cancer is imperative because growing numbers of species are existing at the interface between humans and the environment, making wildlife sentinels for both animal and human health. Therefore, monitoring wildlife cancers could offer interesting and novel insights into potentially unique non-age-related mechanisms of carcinogenesis across species.

On the comparative biology of mammalian telomeres: Telomere length co-evolves with body mass, lifespan and cancer risk

“…Telomere biology is widely assumed to influence cancer risk and thus for different species to evolve different telomere dynamics in response to differing fitness costs of cancer. Cancer occurs in almost all vertebrates, but among wild animals, cancer incidence rates are little studied, but seem to vary considerably (Effron et al 1977;Pesavento et al 2018;Albuquerque et al 2018;Boddy et al 2020). For instance, cancer is rarely reported in long-lived whales, bats or naked mole-rats, while rats and mice are known to be much more prone to cancer (Albuquerque et al 2018).…”

Gut cancer increases the risk for Drosophila to be preyed upon by hunting spiders

“…Individuals always have some tumors, most of which never become lethal (Bissell and Hines 2011; Abu-Helil and van der Weyden 2019). Our understanding of oncogenic phenomena in wild populations of animals is limited, in particular whether tumors that are clinically non-lethal affect the well-being of organisms in the wild (McAloose and Newton 2009;Vittecoq et al 2013;Pesavento et al 2018). If tumor formation is inevitable, it is likely that multicellular organisms have evolved ways to control and tolerate them, perhaps resulting in a trade-off between surviving the tumor and surviving other perils, such as infections or predation (Pavard and Metcalf 2019).…”

Copper isotopes as possible neoplasia biomarkers in captive wild felids

“…Finally, as described by Pesavento et al (), several iatrogenic or environmental factors, such as environmental toxins, infectious agents, chronic stress or inbreeding, are considered as possible neoplasia contributors through their immunosuppression effect.…”

“…According to the literature, neoplasia is a growing concern in captive wild animals (Madsen et al, 2017;McAloose & Newton, 2009;Pesavento, Agnew, Keel, & Woolard, 2018). As captive animals are living longer compared to their wild counterparts (Tidière et al, 2016) and are under continuous veterinary care, neoplasias are more frequently diagnosed and encountered in captivity (Effron, Griner, & Benirschke, 1977;Hubbard, Schmidt, & Fletcher, 1983;Lombard & Witte, 1959;Madsen et al, 2017;Owston, Ramsay, & Rotstein, 2008).…”