Kocikowski, M.; Yebenes Mayordomo, M.; Alfaro, J. A.; Parys, M.

In the quest for improved therapeutics targeting immune checkpoints (ICs), we turn to spontaneously developing dog (canine) cancers, which are unique models that genetically and clinically mirror human equivalents. Despite its potential, canine cancer immunology remains largely unexplored. Here, we examine the RNA-seq-based expression of 44 ICs across 14 canine cancer types and an extensive human dataset. We unveil diverse canine IC expression patterns and unique human IC signatures that reflect the histological type and primary site of cancer. We uncover a striking similarity between canine brain cancers, osteosarcoma, and their human counterparts, identifying them as prospective immunotherapy models. Four ICs - CD160, A2AR, NKG2A, and OX40 - are key to the differences observed between species. Moreover, individual patient IC signatures exhibit varying alignment with their respective cancer types, a finding with profound implications for personalized human therapy. This exploration illuminates new aspects of canine and human cancer immunology, setting the stage for discoveries at their crossroads.