Cancer is the leading cause of death in dogs worldwide. Every year approximately 4 million dogs will be diagnosed with some form of cancer, and 50% of all dogs over the age of 10 will die as a result of developing the disease.

Canine hemangiosarcoma is a malignant tumor that originates from pluripotent bone marrow-derived progenitor cells, and it is ultimately fatal. Despite advances in treatment, dogs with visceral or cardiac hemangiosarcoma still have a poor prognosis and the disease is almost always incurable. Even in dogs with apparently localized disease, hemangiosarcoma cannot be cured by local therapy and adjuvant chemotherapy, and disseminated relapses inevitably occur after treatment. Reported median survival times after surgery and adjuvant doxorubicin-based chemotherapy range from 3 to 12 months, depending on the clinical stage at admission.

Likewise, angiosarcoma is an extremely aggressive cancer in human beings, although rare, accounting for 0.01%–0.1% of all cancers. Conversely, hemangiosarcoma is common in dogs. Recent transcriptomic analysis identified shared genetic alterations, underscoring a highly conserved biological behavior of hemangiosarcoma in both species. Due to the above, the canine model offers a unique opportunity to investigate new methods of stratification and to develop more effective ways to treat and prevent hemangiosarcoma, bridging the gaps and hopefully helping both, dogs and human beings.