Résumé
Cancer is a disease that affects the control of cell proliferation in many multicellular lineages. Nonetheless, little is known about the extent of conservation of the biological traits and ecological factors that promote or inhibit tumorigenesis across the metazoan tree. Particularly, changes in food quantity and quality have been linked to increased cancer incidence in humans, an outcome of evolutionary mismatch. Here, we apply evolutionary ecology principles to test the hypothesis whether food availability, regardless of the multicellular lineage considered, should govern tumorigenesis. We used two phylogenetically unrelated model systems, namely the cnidarian Hydra oligactis and the fish Danio rerio to investigate the impact of resource availability on tumor emergence and progression. Individuals from healthy and tumor-prone lines were placed on four diets that differed in feeding frequency and quantity. For both models, frequent overfeeding favored tumor emergence, while lean diets appear more protective. When investigating tumor progression, high food availability promoted it, whereas low resources controlled it, but without curing the animals. We discuss our results in light of current ideas about the possible conservation of basic processes governing cancer in metazoans (including ancestral life history trade-offs at the cell level) and in the framework of evolutionary medicine.