Antoine Dujon

(6) Conclusion: We need to control for species popularity in future comparative oncology studies using captive animals. This is something already done in comparative studies looking at drivers of parasite diversity.

(5) Reproduction: Invasive placentation no longer associated with higher cancer mortality rates when the popularity of a species is accounted for.

(4) Reproduction: The negative association between gestation length and tumour prevalence in mammals still present, but more uncertain, and the baseline tumours rates are underestimated due to the above mentioned popularity biases

(3) Reproduction: The predicted effect of clutch size on tumour prevalence in birds double when species popularity is taken in account.

(2) Mutations: Similarly, the small trend between germinal cell mutation rate and cancer mortality recently observed is gone when the popularity of species are controlled for.

(1) Peto's paradox: Once the popularity of a species is taken in account the small positive association between body mass and tumour prevalence recently observed in vertebrates is gone.

The Cost of Fame: Strong Biases in Comparative Oncology of Captive Species Comparative oncology is a rapidly expanding field that seeks to explain variation in cancer risk across species by examining trends between tumour prevalence and key risk factors such as body mass, lo...

www.biorxiv.org/content/10.1...

🚨In our latest preprint 🚨 we discovered that tumour prevalence is higher among captive species that enjoy greater public and scientific popularity and this is creating serious bias in comparative oncology studies (link to the paper bellow).

Here is what we found 👇👇👇

A tumoural hydra from my laboratory with a lot of supernumerary tentacles (only tumoural individuals develop that many tentacles), and a little bud growing on top of it. We nickname those hydras "pumpkin" because the tumour grow so big it turns hydras into a pumpkin shape.

The Role of Selection for Function in Aging and Chronic Diseases: A Novel Evolutionary Perspective This conceptual diagram shows how aging alters selection within the body: strong early-life Darwinian selection prevents aberrant structures, while weakened selective pressure in later life allows pe...

A pleasure to have contributed to this very stimulating manuscript proposing a novel hypothesis on how some pathologies of senescence structure themselves to persist over period of time of years to decades.

onlinelibrary.wiley.com/doi/10.1111/...

Towards a more robust comparative oncology: a Bayesian reanalysis of Peto’s paradox and discussion of comparative cancer risk studies in vertebrates | Royal Society Open Science The multistage carcinogenesis model predicts that cancer risk should increase with body size and longevity owing to greater cell numbers and divisions, which provide more opportunities for mutations. ...

Towards a more robust comparative oncology: a Bayesian reanalysis of Peto’s paradox and discussion of comparative cancer risk studies in vertebrates
royalsocietypublishing.org/doi/10.1098/...

Do they reproduce by splitting like real life planaria?

Interesting, what kind of diseases? We have had students working in my lab on tumours in freshwater hydra, I can forward them the position description!

A freshwater Hydra from my lab with a tumour so big it looks like more a pumpkin with tentacles rather than an hydra. It's more a tumour than anything else yet it can still eat.

Simply keeping observed prevalences constant for each species but shuffling the observed number of necropsies between species is enough to have widely different effect sizes with trends going in different directions for some groups.

Are small trends observed between body mass and longevity enough to refute Peto's paradox? I don't think so, and in my new paper I show that those trends are so uncertain that we cannot conclude much from them. We need better stats in those studies.

royalsocietypublishing.org/doi/epdf/10....

Peto’s paradox’s relevance is off the scale | Aging Aging | doi:10.18632/aging.206258. Mirre J.P. Simons

A nice short paper arguing that a small significant trend between body size and cancer risk is not enough to disprove Peto's paradox. I agree with the author we need null models when we test the effect of a risk factor on cancer in comparative studies

doi.org/10.18632/agi...

I would be shame if funding to study tumoral processes in hydra gets discontinued. I am really keen to know why so far only one species of hydra develop tumours and not the others!

📰 ❤️ 🦠 New paper out!

In this study, we found that transmissible tumours, much like some parasites, can change the way their host looks and behaves to benefit themselves.

Link to the paper:
elifesciences.org/articles/97271

Recently reviewed a fundamentally flawed paper, two reviewers agreed with me, paper got rejected from big journal, a few weeks later paper pop in another big journal word for word with zero changes, and now it's picked up by new agencies spreading the wrong message as being a certainty...

Caution is needed here: the rise in cancer rates relative to body size is far less pronounced than predicted by their size. The data is exclusively derived from zoo animals, raised under conditions different from those in the wild with a limited number of necropsies available for each species.

Many thanks!

Has anyone quantified how much energy it takes for a cell to repair a DNA strand break (perhaps in term of number of ATP molecules, joules or anything similar)? #scisky #science

If you're an Australian student interested in exploring the impact of human activities on wildlife and considering an honours project in 2025, I have a couple of exciting opportunities you might want to check out! Send me an email! #scisky #cancer #evolution #Australia

Beyond Peto’s paradox: expanding the study of cancer resistance across species Abstract. Peto’s paradox, which highlights the lower-than-expected cancer rates in larger and/or longer-lived species, is a cornerstone of discussions at t

New paper in Evolution examining how the logic behind Peto's paradox can be applied to various aspects of cancer resistance across species. We highlight the importance of making hypotheses when investigating the effects of risk factors across species. #scisky

doi.org/10.1093/evol...

Neat trick! I will try it too!

I tried linalool (I used it to relax freshwater hydras too) but they twist, do not relax and are not happy anymore. 😅 It may have to do with the concentration (I used 1mM as for the hydras) but I have not made extensive tests. Worth me trying some more.

They are Cura pinguis. I have had issues taking good pictures because they move too fast under my dissecting microscope (nearly all of them are blurry). Any advice on prevent them to move too much without killing them? I need better pics for my talks and would be happy to send them to you.

A happy native Australian planaria culture I maintain in my lab.
#scisky