Stro-1 originally resulted from antibody production using CD34+ bone marrow cells as the immunogen. The Stro-1 antibody has since been used considerably for the identification and isolation of different types of mesenchymal stem cells (MSCs), such as in FACS or immunostaining. Western blot analysis with the Stro-1 antibody has identified a 75-kDa protein expressed on the surface of endothelial cells, some cancer cell lines, and adipose-derived stem cells. There is little knowledge of the protein function, but its expression in MSCs is believed to be an induced event.