Cancer in Amphibia, a rare phenomenon?

Abstract

Compared to other animals, the spontaneous occurrence of tumors in wild amphibians is relatively rare, generally limited to specific populations or species.The number of reports of spontaneous tumors in amphibians known up to 1986 was 491 cases in anurans and about 253 cases in urodeles. Similarly, there have been many, unsuccessful attempts to chemically or biologically induce tumors in amphibians. With these considerations, it is inevitable to wonder: do urodeles and anurans have an inherent resistance to cancer? Here, we review the spontaneous and induced occurrence of tumors in amphibians in a timeline, as well as failed attempts to induce tumors in these amphibians. Indeed, recent studies seem to indicate that there is a relationship between regeneration and cancer because regenerating tissues seem to resist tumorigenesis, as opposed to nonregenerative tissues of the same amphibian models. Although the mechanisms that allow regenerating tissues to resist tumorigenesis have not been elucidated, it is worth to note that, in addition to the apparent relationship between regeneration and cancer, amphibians possess characteristics that could contribute to their ability to resist the development of neoplastic events. The implications of these features in cancer susceptibility are discussed.

Unraveling the relationship between cancer and life history traits in vertebrates

“…In this work, we have established the novel findings that squamates and amphibians both have a positive relationship between body mass and neoplasia prevalence, and amphibians also have a positive relationship between body mass, lifespan, and cancer. It has been proposed that regenerative capacities, as observed in some amphibian species, may be associated with tumor suppression mechanisms 28,29 , and that regeneration in amphibians, unlike mammals, does not necessarily result in increased cancer prevalence 30,31 . This hypothesis needs further exploration since we found that amphibians had lower neoplasia and cancer prevalence than mammals and squamates, but higher than birds.…”

Amphibian-Derived Natural Anticancer Peptides and Proteins: Mechanism of Action, Application Strategies, and Prospects

“…Due to their natural resistance to cancer, spontaneous tumors in amphibians are rare, and even in laboratory settings, it is challenging to induce tumors using chemical or biological methods. This natural advantage makes amphibians a promising source for mining anticancer substances [ 134 ]. With the advent of new technologies and methods to enhance drug efficacy and promote drug development and clinical transformation, it is expected that more highly effective anticancer substances will be discovered and elucidated.…”