GAST and Hematemesis: It has been suggested that the production of gastrin by a portion of these neoplasms in dogs and the resultant clinical signs of vomiting and hematemesis may lead to an earlier diagnosis and contribute to a favorable prognosis; however, gastrointestinal signs have also been documented in a dog with a GB NEN that was negative for gastrin, indicating that the clinical presentation associated with this neoplasm is likely multifactorial [10,44].