2017 ACVIM Forum Research Abstract Program

HER2/neu is an epidermal growth factor receptor tyrosine kinase that is expressed in human cancers of the prostate, breast, ovary, stomach, and colon. HER2/neu expression is reported in up to 60% of human pediatric osteosarcomas, where increased expression correlates with aggressive biologic behavior and an increased risk of metastasis. Contrary to the membranous expression seen in carcinomas, HER2/neu expression in OSA is principally cytoplasmic. In canine patients, one previous retrospective study reported HER2 expression in 4/10 primary tumor samples, with a suggestion that HER2 expression correlated with decreased survival. We therefore hypothesized that HER2 expression in canine OSA denotes a more aggressive disease phenotype.