Cancer remains a mysterious disease, with some animals being more prone to it than others, despite the number of cells in their bodies. This paradox, known as Peto’s paradox, has led researchers to investigate why some large animals like whales and elephants have lower cancer rates than expected. A decade-long effort by UC Santa Barbara anthropologist Amy Boddy and her team has resulted in a comprehensive compilation of cancer prevalence across 292 species of vertebrates, shedding light on the strategies of species with exceptional cancer resistance.
The study revealed that all animals are susceptible to cancer, suggesting that multicellularity itself poses a risk due to genetic mutations that can lead to uncontrolled tissue growth characteristic of cancer. By analyzing cancer prevalence across species, researchers were able to control for various factors and found that animals with longer gestation times, typically associated with larger bodies, tend to have lower cancer rates. This aligns with the idea that bigger, long-lived species invest more resources in somatic maintenance to combat mutations and defend against cancer.
Evolutionary history plays a significant role in how different species have developed strategies to avoid cancer. For example, elephants have 20 copies of a tumor suppressor gene, while others may have lower somatic mutation rates to slow the accumulation of mutations leading to cancer. Each species has a unique story and genetic trade-offs that influence their defenses against cancer, making it difficult to identify a general pattern across vertebrates. This diversity in strategies highlights the ongoing evolutionary battle between animals and cancer, with species evolving different ways to combat the disease.
The extensive dataset compiled by Boddy and her team could provide valuable insights for cancer research, as it includes a wide range of species that exhibit varying susceptibilities to cancer. This could lead to better models for studying cancer and rare diseases, beyond the traditional focus on rodent models. The researchers plan to further investigate specific types of cancer across species to understand if different members of the primate family, for example, experience similar types of cancers as humans. They are also interested in exploring the underlying mechanisms that contribute to the development of cancer in species with higher prevalence rates.
Overall, the study offers a glimpse into the complex relationship between animals and cancer, highlighting the diverse strategies that individual species have evolved to combat the disease. This research opens up new possibilities for understanding cancer across different species and could pave the way for developing more effective treatments based on unique evolutionary adaptations. By exploring the genetic, evolutionary, and environmental factors that influence cancer prevalence, researchers are moving closer to unraveling the mysteries of this devastating disease.