This research focuses on gastric cancer, a disease with no effective treatments in dogs. Belgian Tervuren and Sheepdogs are commonly diagnosed between 8–10 years of age, shortening their lifespan by approximately six years. Our goal is to identify the genetic basis of this cancer and its two tumor subtypes, which could have a big impact by leading to a genetic test to identify dogs at high risk. This test would support early screening and diagnosis, inform breeding decisions, and reduce disease frequency over time. Understanding the molecular mechanisms could also lead to improved therapies in the long-term.