Can postfertile life stages evolve as an anticancer mechanism?

by Fr édéric Thomas, Mathieu Giraudeau, François Renaud, Beata Ujvari, Benjamin Roche, Pascal Pujol, Michel Raymond, Jean-François Lemaitre, Alexandra Alvergne Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologists for over 50 years. We propose that existing adaptive explanations have underestimated in their formulation an important parameter operating both at the specific and the individual levels: the balance between cancer risks and cancer defenses. During their life, most multicellular organisms naturally accumulate oncogenic processes in their body. In parallel, reproduction, notably the pregnancy process in mammals, exacerbates the progression of existing tumors in females. When, for various ecologi cal or evolutionary reasons, anticancer defenses are too weak, given cancer risk, older females could not pursue their reproduction without triggering fatal metastatic cancers nor even maintain a normal reproductive physiology if the latter also promotes the growth of existing oncogenic processes, e .g., hormone-dependent malignancies. At least until stronger anticancer defenses are selected for in these species, females could achieve higher inclusive fitness by ceasing their reproduction and/or going through menopause (assuming that these traits are easier to select than anticancer defenses), thereby limiting the risk of premature death due to metastatic cancers. Because relatively few species experience such an evolutionary ...
Source: PLoS Biology: Archived Table of Contents - Category: Biology Authors: Source Type: research