*Aurora Nedelcu (University of New Brunswick, Canada)* *"Cancer and the Evolution of Multicellularity: Limitations of Current Views and Paradigms"* *December 16th, 2024, 5pm (French time, UTC+1)* *PhilInBioMed Seminar Series, organized by the University of Bordeaux, France* *Abstract* The evolution of multicellularity requires the integration of single cells into new functionally, reproductively and evolutionary stable multicellular individuals. As part of this process, a change in levels of selection occurs, with selection at the multicellular level overriding selection at the cell level. The stability of multicellular individuals is dependent on a combination of mechanisms that control within-group evolution, by both reducing the occurrence of somatic mutations as well as supressing somatic selection. Nevertheless, mutations that, in a particular microenvironment, confer mutant cell lineages a fitness advantage relative to normal somatic cells do occur, and can (but not always) result in cancer. This talk will highlight several views and paradigms that relate the evolution of multicellularity to cancer. Cancer is generally understood as a disease of multicellularity, and is interpreted in different frameworks: (i) a breakdown of cooperative behaviors (i.e., cheating) underlying the evolution of multicellularity, (ii) a disruption of molecular networks established during the emergence of multicellularity to impose constraints on single-celled units, or (iii) an atavistic state resulting from reactivating primitive programs that originated in the earliest unicellular species. Several assumptions are common in all the views relating cancer as a disease to the evolution of multicellularity. For instance, cancer is considered a reversal to selfish unicellularity, and cancer cells are thought to resemble unicellular organisms and benefit from ancestral-like traits. I will discuss potential limitations of current views and paradigms and show how different perspectives can provide novel insights with potential therapeutic implications. *Zoom link: please contact Thomas Pradeu * *Detailed information:* Aurora Nedelcu (Univ. New Brunswick, Canada) (virtual), Cancer and the evolution of multicellularity: limitations of current views and paradigms philinbiomed.org Sincerely, Thomas Pradeu CNRS Research Director in Philosophy of Science Immunology Unit ImmunoConcEpT, UMR5164, CNRS & University of Bordeaux Presidential Fellow, Chapman University, CA, USA Team Leader Conceptual Biology and Medicine Team Coordinator of the Philosophy in Biology and Medicine Network (PhilInBioMed) Thomas Pradeu (to subscribe/unsubscribe the EvolDir send mail to golding@mcmaster.ca)