My group is investigating the mechanisms that influence the progression and metastasis of mesenchymal tumors, i.e., sarcomas. We wish to learn how the mesenchymal nature of these tumors relates to the mesenchymal state of carcinoma cells that have undergone an epithelial-to-mesenchymal transition (EMT). Our studies use cell lines derived from a mouse model of metastatic osteosarcoma (OS) and have shown that co-injection of primary wild-type mesenchymal stromal cells (MSCs) promotes the ability of primary OS tumor cells to form subcutaneous tumors and enables the formation of metastases by these tumors. Our experiments are directed toward identifying the MSC-induced signals and how they correlate with the tumor-initiating powers of sarcoma cells and whether these mechanisms are broadly applicable to other mesenchymal tumor types.