Cross-species cancer research

Andrew Robson explores cross-species cancer research and how cancer studies in animals contribute to understanding and treating human cancers.

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Cancer is a universal challenge that affects humans and animals alike. While often seen as a human disease, cancer also impacts pets and wildlife. This shared vulnerability has opened doors to research benefiting both veterinary and human medicine. By studying cancer in animals, scientists gain insights that drive innovations in diagnosis and treatment across species.

Cancer as a shared disease amongst animals and humans

Cancer occurs in nearly all species, with mechanisms that are strikingly similar. African wildlife, for example, faces significant cancer challenges. Giraffes in South Africa are affected by sarcoids, a type of skin tumour linked to bovine papillomavirus (BPV). Cape mountain zebras and sable antelopes have also been found with similar growths, underscoring the virus’s impact across species. These findings are particularly relevant as humans are similarly affected by papillomaviruses, which are linked to cervical and other cancers. 

Meanwhile, Tasmanian devils in Australia contend with transmissible cancers, such as devil facial tumour disease, offering additional insights into cancer’s mechanisms of transmission and immune evasion.

But mother nature is a fierce, resilient force and certain animals exhibit remarkable resistance or even immunity to cancer, offering fascinating insights into potential protective mechanisms. For instance, naked mole-rats, known for their exceptional longevity, rarely develop cancer due to a unique mechanism involving high-molecular-weight hyaluronan, which prevents cells from overcrowding and forming tumours. 

Similarly, some whale species, such as bowhead whales, display resistance to cancer despite their large body size and long lifespans. This phenomenon, often referred to as Peto’s paradox, may be attributed to enhanced DNA repair mechanisms and additional tumour suppressor genes. Studying these species provides valuable clues that could inform innovative cancer prevention and treatment strategies in humans.

These cases highlight the ecological and biological reach of cancer. The shared factors influencing cancer, such as carcinogens, genetic mutations, and aging, make animals invaluable in understanding the disease and developing therapies.

The contribution of man’s best friend to cancer treatments

While the understanding of cancer in wild populations is still evolving, dogs continue to play a crucial role in cancer research due to their natural development of tumours similar to those in humans. Unlike laboratory mice bred for specific cancers, dogs offer real-world models for disease progression and treatment responses. Their lifespans of 10-15 years, compared to the human lifespan of 80+ years, allow researchers to evaluate therapies over shorter periods.

One notable breakthrough is the canine melanoma vaccine. Originally developed to treat dogs with advanced melanoma, this immunotherapy has inspired similar approaches in human medicine. 

Additionally, research into canine lymphoma has significantly enhanced the understanding of drug resistance and contributed to the development of improved chemotherapy protocols for humans. Drugs such as chlorambucil, cyclophosphamide, L-asparaginase, vincristine, and prednisone have all benefited from canine studies. 

For instance, chlorambucil dosing and side effect management have been refined, while cyclophosphamide dosing schedules and combination therapies have been optimised. L-asparaginase administration methods have been improved for human leukaemia and lymphoma treatments, and vincristine regimens have been fine-tuned to reduce resistance in human patients. 

Moreover, prednisone has been better utilised in combination therapies, enhancing outcomes for human lymphoma patients. Studies of osteosarcoma and soft tissue sarcomas in dogs have also guided advancements in limb-sparing surgeries and bone cancer treatments for children facing similar cancers. These contributions from veterinary research have had a profound impact on human oncology, offering new insights and improving treatment protocols.

The One Health perspective

The One Health concept highlights the interconnectedness of human, animal, and environmental health, making it particularly relevant in cancer research. Shared exposures to carcinogens, such as industrial pollutants, drug residues in water, and second-hand smoke, provide valuable opportunities to develop prevention strategies that benefit all species. 

Cross-species cancer research reinforces the idea that studying cancer in animals not only enhances the understanding of the disease but also leads to improved health outcomes for humans, pets, and wildlife alike. 

As we continue to advance cancer research, it’s essential that we uphold the highest standards of animal welfare, recognising our responsibility as custodians to ensure ethical practices that benefit both scientific progress and the well-being of all species.