STRO-1 is a cell surface antigen recognized by mAb STRO-1. It is expressed by bone marrow mesenchymal stromal cells and nucleated erythroid precursors, but not by committed hematopoietic progenitors. In combination with glycophorin A (GPA), STRO-1 is a useful marker for identification of mesenchymal stem cells. It has been reported that the STRO-1+/GPA- bone marrow cell subset can be used as a universal stromal feeder layer for hematopoietic stem/progenitor cells. This multipotent subset of cells can differentiate into fibroblasts, adipocytes, osteoblasts, chondrocytes, and vascular smooth muscle-like cells.