RESEARCH COMMUNICATIONS OF THE 28th ECVIM-CA CONGRESS

RNA in situ hybridization (RNAscope®, ACDBio) was used to evaluate 11 canine osteosarcoma samples for mRNA expression of canine EP4R. RNAscope technology is a modification of in situ hybridization for detection of RNA in formalin‐fixed, paraffin‐embedded tissue sections. To quantify RNAscope signals in tissue sections, an advanced digital pathology image analysis system (HALO, Indica Labs) was utilized. This software allows for determination of target RNA copy number at the cellular level. Data was expressed as copy number for EP4R with that signal compared to the housekeeping target (B‐actin, positive control gene). No ethical approval was obtained as this study did not involve a prospective evaluation and utilized tissue samples left‐over following patient clinical treatment (amputation) or diagnostic (biopsy) procedures for osteosarcoma.