2017 ACVIM Forum Research Abstract Program

When previously reported (ACVIM 2014), the original data set showed no correlation between HER2/neu expression and TTP or OS. However, in this report, only patients that underwent standard of care amputation and chemotherapy were included in the TTP and OS analysis, revealing a trend toward shorter TTP and OS for dogs with tumors that highly express HER2/neu. Prospective studies will be required to determine whether a statistically significant correlation exists between HER2/neu status and patient outcome. Nevertheless, taken together, these data show that the majority of canine OSA express HER2/neu, and that dogs with tumors that have high HER2/neu combined scores have a tendency toward earlier metastasis and decreased OS. These data support the evaluation of HER2/neu targeted immunotherapies in both the prevention and possible treatment of metastatic OSA. Osteosarcoma (OSA) is the most common bone tumor in children and dogs; however, despite aggressive treatment, little improvement in survival times have been achieved in either dogs or people over the past 15 years. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and play a fundamental role in cancer. Our laboratory previously identified a unique miRNA expression signature associated with canine OSA and found miR-34a expression to be significantly decreased in canine OSA tumors compared to normal canine osteoblasts. These data are concordant with recent studies demonstrating that miR-34a functions as a tumor-suppressor gene in human OSA and that loss of miR-34a is associated with a poor prognosis in human OSA patients. We hypothesize that loss of miR-34a generates a pattern of gene dysregulation that contributes to the pathogenesis of canine OSA.