Cancer Susceptibility as a Cost of Reproduction and Contributor to Life History Evolution

Abstract

Reproduction is one of the most energetically demanding life-history stages. As a result, breeding individuals often experience trade-offs, where energy is diverted away from maintenance (cell repair, immune function) toward reproduction. While it is increasingly acknowledged that oncogenic processes are omnipresent, evolving and opportunistic entities in the bodies of metazoans, the associations among reproductive activities, energy expenditure, and the dynamics of malignant cells have rarely been studied. Here, we review the diverse ways in which age-specific reproductive performance (e.g., reproductive aging patterns) and cancer risks throughout the life course may be linked via trade-offs or other mechanisms, as well as discuss situations where trade-offs may not exist. We argue that the interactions between host–oncogenic processes should play a significant role in life-history theory, and suggest some avenues for future research.

A review of the methods used to induce cancer in invertebrates to study its effects on the evolution of species and ecosystem functioning

“…Potential examples are the placozoan Trichoplax adhaerens , which can tolerate levels of radiation of 248.6 Gy by overexpressing genes involved in DNA repair (Fortunato et al, 2021), or the planarians Girardia ( Dugesia ) tigrina and Polycelis feline which recover quickly from an acute sublethal exposure to ultraviolet radiation without developing cancer (Kalafatić et al, 2006). Such results are important to consider because they make it possible to explore trade‐offs between the ability of a species to repair its DNA, other damages leading to cancer, and the maintenance of other important functions such as movement or reproduction (Boutry et al, 2020; Dujon et al, 2022). The use of a positive control during such experiments can help identify such situations.…”

The effect of placentation type, litter size, lactation and gestation length on cancer risk in mammals

“…Reproduction is one of the most energetically demanding life-history stages, with the lactation length being typically more costly than gestation itself [50]. Therefore, breeding individuals are expected to experience trade-offs, where energy is diverted away from self-maintenance (cell repair, immune function) towards reproduction, favouring the development of tumours [5,12]. However, the effect on the fitness may be small, as the cancer mortality risk of species did not scale with litter size and lactation length.…”

“…Those high physiological costs could exacerbate the progression of existing tumours but not necessarily to a point at which they would result in an increase mortality risk. Indeed, species are expected to have evolved over evolutionary times anti-cancer defences to at least partially counter those negative effects on their health [5,12]. Placentation is also a key feature of mammalian reproduction.…”

“…It is increasingly suggested that oncogenic processes have been influencing the evolutionary ecology of their hosts since the dawn of multi-cellularity, approximately 1 billion years ago [3,4]. Tumoral cells, especially malignant ones, can be detrimental to the host by directly or indirectly imposing fitness costs on them, reducing for instance their survival and/or their reproductive potential [4][5][6][7]. These effects have in return promoted the evolution of defence mechanisms in hosts [8], as well as compensatory adaptations [9].…”