Publications by authors named "Dujon A"

Article Synopsis
  • Peto's paradox reveals that larger and longer-lived species often have lower-than-expected cancer rates, sparking interest in how they achieve cancer resistance despite traits that might suggest higher risks.
  • The research suggests shifting focus to other species with characteristics that increase cancer risk but still show unexpected resistance, aiming to discover potential therapies for humans.
  • The study emphasizes the need to consider species that balance cancer risks and defenses while addressing challenges posed by human activities, and suggests that examining transmissible cancers could provide insights into natural suppression of cancer spread.
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While it is recognised that most, if not all, multicellular organisms harbour neoplastic processes within their bodies, the timing of when these undesirable cell proliferations are most likely to occur and progress throughout the organism's lifetime remains only partially documented. Due to the different mechanisms implicated in tumourigenesis, it is highly unlikely that this probability remains constant at all times and stages of life. In this article, we summarise what is known about this variation, considering the roles of age, season and circadian rhythm.

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Article Synopsis
  • - Tumorigenesis is often linked to Darwinian processes like natural selection, but advancing tumors also need the right group phenotypic composition (GPC) to thrive.
  • - The selective processes affecting tumor GPCs differ from classical natural selection because tumors aren't true evolutionary individuals and lack heritable fitness variation.
  • - The authors suggest that it's misleading to view tumorigenesis solely through a Darwinian lens; instead, understanding cancer progression requires recognizing that genetic and phenotypic diversity contributes to tumor success through a process known as "selection for function."
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While most cancers are not transmissible, there are rare cases where cancer cells can spread between individuals and even across species, leading to epidemics. Despite their significance, the origins of such cancers remain elusive due to late detection in host populations. Using , which exhibits spontaneous tumour development that in some strains became vertically transmitted, this study presents the first experimental observation of the evolution of a transmissible tumour.

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Recent theoretical advances in the One Health approach have suggested that cancer pathologies should be given greater consideration, as cancers often render their hosts more vulnerable to infectious agents, which could turn them into super spreaders within ecosystems. Although biologically plausible, this hypothesis has not yet been validated experimentally. Using a community of cnidarians of the Hydra genus (Hydra oligactis, Hydra viridissima, Hydra vulgaris) and a commensal ciliate species (Kerona pediculus) that colonizes them, we tested whether tumoral polyps of H.

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The last few years have seen a surge of interest from field ecologists and evolutionary biologists to study neoplasia and cancer in wildlife. This contributes to the One Health Approach, which investigates health issues at the intersection of people, wild and domestic animals, together with their changing environments. Nonetheless, the emerging field of wildlife cancer is currently constrained by methodological limitations in detecting cancer using non-invasive sampling.

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Article Synopsis
  • Tumours are common in multicellular organisms and impact the evolution and biology of species, making suitable laboratory models essential for studying these processes.
  • The cnidarian Hydra oligactis is highlighted as a promising model for research, showing both transmissible and non-transmissible tumours, allowing diverse experimental approaches.
  • This study reveals that Australian hydras can also develop tumours similar to those found in Europe, confirming their potential for ecological and evolutionary studies on how host organisms interact with tumours.
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Growing evidence indicates that human activities are causing cancer rates to rise in both human and wildlife populations. This is due to the inability of ancestral anti-cancer defences to cope with modern environmental risks. The evolutionary mismatch between modern oncogenic risks and evolved cancer defences has far-reaching effects on various biological aspects at different timeframes, demanding a comprehensive study of the biology and evolutionary ecology of the affected species.

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Background: Pancreatic cancer, predominantly characterized by ductal adenocarcinoma (PDAC) accounts for 90% of cases and is the fourth leading cause of cancer-related deaths globally. Its incidence is notably increasing. This poor prognosis is primarily due to late-stage diagnosis (approximately 70% to 80% of patients are diagnosed at an advanced stage), aggressive tumor biology, and low sensitivity to chemotherapy.

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Cancer is a disease that many multicellular organisms have faced for millions of years, and species have evolved various tumour suppression mechanisms to control oncogenesis. Although cancer occurs across the tree of life, cancer related mortality risks vary across mammalian orders, with Carnivorans particularly affected. Evolutionary theory predicts different selection pressures on genes associated with cancer progression and suppression, including oncogenes, tumour suppressor genes and immune genes.

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Cancer is an inevitable collateral problem inherent in the evolution of multicellular organisms, which appeared at the end of the Precambrian. Faced to this constraint, a range of diverse anticancer defenses has evolved across the animal kingdom. Today, investigating how animal organisms, especially those of large size and long lifespan, manage cancer-related issues has both fundamental and applied outcomes, as it could inspire strategies for preventing or treating human cancers.

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Since the emergence of a transmissible cancer, devil facial tumour disease (DFT1), in the 1980s, wild Tasmanian devil populations have been in decline. In 2016, a second, independently evolved transmissible cancer (DFT2) was discovered raising concerns for survival of the host species. Here, we applied experimental and modelling frameworks to examine competition dynamics between the two transmissible cancers in vitro.

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Introduction: (TG) is a common protozoan parasite infecting approximately one third of the human population. Animal studies have shown that this parasite can manipulate its host behavior. Based on this, human studies have assessed if TG can be involved in mental health disorders associated with important behavioral modifications such as schizophrenia.

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Article Synopsis
  • Wildlife is facing increased risks from cancer-causing substances, which affects their behavior and population dynamics.
  • The study examined the effects of cadmium, a carcinogen, on wild planaria's activity over a 14-day period, divided into exposure and recovery phases.
  • Results showed that cadmium-exposed planaria were less active but eventually returned to pre-exposure activity levels, indicating that cancer risk factors can change behavioral patterns and highlight the need for advanced research in behavioral ecology.
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Avian embryos develop in an egg composition which reflects both maternal condition and the recent environment of their mother. In birds, yolk corticosterone (CORT) influences development by impacting pre- and postnatal growth, as well as nestling stress responses and development. One possible mechanism through which maternal CORT may affect offspring development is via changes to offspring DNA methylation.

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The presence of doubly uniparental inheritance (DUI) in bivalves represents a unique mode of mitochondrial transmission, whereby paternal (male-transmitted M-type) and maternal (female-transmitted F-type) haplotypes are transmitted to offspring separately. Male embryos retain both haplotypes, but the M-type is selectively removed from females. Due to the presence of heteroplasmy in males, mtDNA can recombine resulting in a 'masculinized' haplotype referred to as M-type.

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Article Synopsis
  • The study investigates how food availability influences tumor development in two unrelated multicellular organisms: Hydra oligactis (a cnidarian) and Danio rerio (a fish).
  • Results show that overfeeding increases the likelihood of tumor formation, while lean diets offer some protection against tumor emergence.
  • The findings suggest that basic biological processes affecting cancer may be conserved across different life forms, with implications for understanding cancer through the lens of evolutionary medicine.
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Article Synopsis
  • The hygiene hypothesis suggests that reduced exposure to infectious agents leads to various diseases, including cancer and autoimmune disorders, but lacks proper testing on animals.
  • This study analyzed 112 mammalian species in zoos to investigate the link between the richness of parasitic species in their natural habitats and cancer risk in captivity.
  • The results showed no strong evidence that higher parasite richness increased cancer risk in zoo mammals, indicating that the hygiene hypothesis may not explain cancer risk as proposed.
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Reproduction is a central activity for all living organisms but is also associated with a diversity of costs that are detrimental for survival. Until recently, the cost of cancer as a selective force has been poorly considered. Considering 191 mammal species, we found cancer mortality was more likely to be detected in species having large, rather than low, litter sizes and long lactation lengths regardless of the placentation types.

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Hydras are freshwater cnidarians widely used as a biological model to study different questions such as senescence or phenotypic plasticity but also tumoral development. The spontaneous tumors found in these organisms have been so far described in two female lab strains domesticated years ago (Hydra oligactis and Pelmatohydra robusta) and the extent to which these tumors can be representative of tumors within the diversity of wild hydras is completely unknown. In this study, we examined individuals isolated from recently sampled wild strains of different sex and geographical origin, which have developed outgrowths looking like tumors.

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Background: Why humans historically began to incorporate spices into their diets is still a matter of unresolved debate. For example, a recent study (Bromham et al. There is little evidence that spicy food in hot countries is an adaptation to reducing infection risk.

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A plethora of intrinsic and environmental factors have been shown to influence the length of telomeres, the protector of chromosome ends. Despite the growing interest in infection-telomere interactions, there is very limited knowledge on how transmissible cancers influence telomere maintenance. An emblematic example of transmissible cancer occurs in the Tasmanian devil (Sarcophilus harrisii), whose populations have been dramatically reduced by infectious cancer cells.

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