Soft tissue sarcoma (STS) encompasses a number of neoplasms that are derived from mesenchymal cells including fibrosarcoma, myxosarcoma, hemangiopericytoma, and undifferentiated sarcoma. In the dog, STSs arise frequently in the dermis/subcutis and represent up to 15% of the neoplasms in this location. Our primary aim of this grant was to collect cases of canine STS for histologic and gene expression analysis. During the first two years of the grant, we have had an excellent recovery rate for our cases with very few being dropped due to quality control issues. Now that we have started the 3rd year, we have chosen the last 100 cases and they are currently being processed.