A study published earlier this month in the journal Nature regarding cancer incidence among mammalian species draws upon data shared by zoos using the Species360 Zoological Information Management System (ZIMS). In the study, researchers found that their results “highlight the key role of life-history evolution in shaping cancer resistance and provide major advancements in the quest for natural anticancer defenses.”
Because cancer results from the accumulation of mutations in tissue cells, it is generally expected that species that growth larger or that live longer will have also higher incidence of cancer than smaller or shorter-lived ones. That is, cancer incidence should be proportional to the species size and longevity. However, in 1977 Sir Richard Peto noted that despite that mice have a 1000-times less cells than humans and have 30 times shorter lifespans, their cancer incidence is similar to that of humans. This has since been known as Peto’s paradox, and was only confirmed in a short number of species.
Until now, a lack of species data prevented rigorous and quantitative comparative analysis of the relationship between size and longevity and cancer incidence across mammals. But decades of species data recorded by zoos now gives researchers the depth and breadth of information needed to examine Peto’s paradox.
To test the paradox, Fernando Colchero and Dalia A. Conde, both of the Species360 Conservation Science Alliance, worked with a team of international collaborators, and analysed a pool of adult mammalian animals represented by data recorded in ZIMS. The study included 110,148 individuals spanning 191 species. Their findings offer conclusive proof that cancer mortality risk is largely independent of both body mass and adult life expectancy across species.
Orsolya Vincze, from the French National Centre for Scientific Research (CNRS), the first author of the study, says: “We concluded that the solution to the Peto’s Paradox lies in the fact that the evolution of greater size and longevity in species has been accompanied by the co-evolution of potent mechanisms of cancer resistance. Our study highlights the value of the incredible work of the zoo and aquariums that integrate and standardize their records in ZIMS.”
Here is an excerpt from full paper:
“…Documenting cancer in wild animals is extremely challenging in most cases owing to the lack of information on the age of individuals, the difficulty retrieving the bodies for necropsy and the likelihood of cancer negatively influencing survival before cancer itself could be detected. Although data on cancer incidence from wild populations would be indispensable to describe natural incidences of malignancies, such data, especially with corresponding ages and demographic histories, are unfortunately still far from our reach.
Therefore, to estimate cancer mortality risk, we used data provided by Species360 and the Zoological Information Management System (ZIMS), an international non-profit organization that maintains a real-time and centralized database of animals under human care (regrouping information from over 1,200 zoos worldwide). Although we recognize that the interpretation of data gathered on zoo animals requires caution, owing to strong human control on the diet, health, mortality factors, environment or standard biological functions of the animals, zoos provide exceptionally high data resolution on the demography and cause of death for a wide range of species.”
This research is possible thanks to the sponsoring partners of the Conservation Science Alliance including Copenhagen Zoo, Mandai Wildlife Group (Singapore), and the World Association of Zoos and Aquariums (WAZA).
Essential data available in ZIMS is made available thanks to the zoos and aquariums that record and share data as part of the global Species360 community. Many of these institutions participate in Species360 through the encouragement of international and regional associations like WAZA, the European Association of Zoos and Aquaria (EAZA), the Association of Zoos and Aquariums (AZA), Zoo and Aquarium Association – Australasia, and more. Together, these Species360 member associations and institutions have made ZIMS one of the largest sets of cross-species data in the world.
View a one-minute explanation by Carlo Manley coauthor of the paper: Large-scale mammal cancer study upholds decades-long paradox.
Read the full paper at Nature.com.
Note: Example of how Arizona highlights his researcher: https://www.eurekalert.org/news-releases/938805