️ Episode 203: Divergent Evolutionary Dynamics of Benign and Malignant Tumors
In this episode of PaperCast Base by Base, we explore how benign and malignant tumors follow different evolutionary trajectories across birds and mammals, and what this reveals about cancer defenses across the tree of life.

Study Highlights:
The authors combine necropsy data on tumor prevalence from hundreds of bird and mammal species with Bayesian multivariate phylogenetic generalized linear mixed models to test how benign and malignant tumors relate to macroevolutionary processes. They show that prevalence of both benign and malignant tumors increases with body mass, confirming that larger-bodied species accumulate more neoplastic growths overall. Only malignant tumors, however, show a negative association with the rate of body size evolution, consistent with stronger adaptive cancer suppression mechanisms in rapidly evolving lineages. In birds, but not mammals, higher lineage diversification rates are linked to higher prevalence of both tumor types, suggesting that speciation-associated genomic instability can come with an increased tumor burden. Together, these patterns indicate that benign and malignant tumors respond differently to evolutionary pressures, with malignancies more tightly constrained by selection on body size evolution while benign tumors remain comparatively unconstrained.

Conclusion:
This work shows that treating benign and malignant tumors as distinct evolutionary phenomena can clarify how cancer resistance arises and help frame new hypotheses about why some lineages are more prone to malignancy than others.

Music:
Enjoy the music based on this article at the end of the episode.

Reference:
Butler G, Baker J, Amend SR, Pienta KJ, Venditti C. Divergent evolutionary dynamics of benign and malignant tumors. Proceedings of the National Academy of Sciences. 2025;122(45):e2519203122. https://doi.org/10.1073/pnas.2519203122

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

Castos player https://basebybase.castos.com

On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics.