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This multi-institutional collaborative study of neoplasia in snakes reviewed medical records of snakes at each facility to determine species prevalence, survival, and methods of treatment. Complete species numbers of snakes were also collected at each facility. In total, 65 species, 133 snakes, and 149 unique neoplasias were included in this study....
Citations
... Early work in comparative oncology found that birds, and to a lesser extent reptiles, develop fewer neoplasms than mammals (12)(13)(14). While single case studies have been reported (15), it has been difficult to estimate true neoplasia prevalence in these taxa. ...
Cancer is pervasive across multicellular species. Are there any patterns that can explain differences in cancer prevalence across species? Using 16,049 necropsy records for 292 species spanning three clades (amphibians, sauropsids and mammals) we found that neoplasia and malignancy prevalence increases with adult weight and decreases with gestation time, contrary to Petos Paradox. Evolution of cancer susceptibility appears to have undergone sudden shifts followed by stabilizing selection. Outliers for neoplasia prevalence include the common porpoise (<1.3%), the Rodrigues fruit bat (<1.6%) the black-footed penguin (<0.4%), ferrets (63%) and opossums (35%). Discovering why some species have particularly high or low levels of cancer may lead to a better understanding of cancer syndromes and novel strategies for the management and prevention of cancer.
... The Exotic Species Cancer Research Alliance (ESCRA) is a neoplasia database established to collect and record neoplasia cases in non-domestic species across facilities, including those not reported in the literature [56,57]. Cases of neoplasia and corresponding treatments are collected from multiple zoological and aquatic institutions, as well as veterinary teaching hospitals and private practices. ...
Reproductive tumors can impact conception, pregnancy, and birth in mammals. These
impacts are well documented in humans, while data in other mammals are limited. An urgent need exists to understand the reproductive impact of these lesions in endangered species, because some endangered species have a documented high prevalence of reproductive tumors. This article documents that the prevalence of both benign and malignant neoplasia differs between African and Asian elephants, with Asian elephants more frequently diagnosed and negatively affected by both.
The prevalence of these tumors across mammalian species is compared, and impact plus treatment options in human medicine are reviewed to inform decision making in elephants. Evidence suggests that reproductive tumors can negatively impact elephant conservation. Future studies that document reproductive outcomes, including the success of various treatment approaches in elephants with tumors will benefit conservation efforts.
... Here we present the first study comparing cancer prevalence within and between tetrapods, which comprises all the extant major vertebrate groups except fish. We obtain necropsy data, including cancer incidence, from mammals, birds, amphibians, turtles, crocodilians, and squamates (lizards and snakes) from multiple zoos as well as from previous publications (Boddy et al., 2020a;Duke et al., 2022). Using the largest dataset to date for most tetrapod groups, we then analyze cancer prevalence within each group in relation to phylogeny, variation in body mass and lifespan among species, and intrinsic cancer risk estimated from species life history traits. ...
... The databases for Allwetter, ZOOM Erlebniswelt, and Birmingham Zoo were all local databases while Rotterdam Zoo data was obtained through local paper reports and the Species360 Zoological Information Management System (ZIMS) with Rotterdam Zoo's authorization. We also incorporated the mammalian necropsy reports from Boddy et al. (2020a) and a dataset of neoplasia (benign or malignant) in snakes from Duke et al. (2022). The dataset of Duke et al (2022) is based on cancer prevalence calculated from the number of biopsies and necropsies on the total number of individuals (live and dead) of each species housed at a given time at participating institutions in the study. ...
... We also incorporated the mammalian necropsy reports from Boddy et al. (2020a) and a dataset of neoplasia (benign or malignant) in snakes from Duke et al. (2022). The dataset of Duke et al (2022) is based on cancer prevalence calculated from the number of biopsies and necropsies on the total number of individuals (live and dead) of each species housed at a given time at participating institutions in the study. Since this prevalence was partly based on live individuals and not strictly on necropsy reports, as was the rest of our data, we performed subsequent analyses both with and without the data from Duke et al. (2022). ...
Cancer rates vary widely across vertebrate groups. Identifying species with lower-than-expected cancer prevalence can help establish new models for unraveling the biological mechanisms underlying cancer resistance. Theoretical predictions suggest that cancer prevalence should be positively associated with body mass and longevity in animals. Yet, in mammals, the best studied vertebrates in terms of cancer, this prediction does not hold true: a phenomenon known as Peto’s paradox. Despite mounting work disentangling the biological basis of Peto’s paradox, it is still relatively unknown whether other major vertebrate groups behave similarly to mammals or might hold new keys to understanding cancer biology. Here, we present the largest dataset available so far on cancer prevalence across all major groups of tetrapod vertebrates: amphibians, birds, crocodilians, mammals, squamates (lizards and snakes), and turtles. We investigated cancer prevalence within and among these groups and its relationship with body mass and lifespan. This is the first study to analyze non-avian reptile groups separately. We found remarkably low cancer prevalence in birds, crocodilians, and turtles. Counter to previous studies, we found that body mass and lifespan are inversely related to cancer prevalence in mammals, although Peto’s paradox still holds true in this group. Conversely, we rejected Peto’s paradox in birds and squamates, as neoplasia prevalence was positively associated with body mass in these groups. The exceptionally low cancer prevalence in turtles and extensive variation in cancer prevalence amongst vertebrate families hold particular promise for identifying species with novel mechanisms of cancer resistance.
