Adult bone marrow is the site of intense hematopoietic activity that is housed in a unique
connective tissue called bone marrow stroma. The stroma establishes a niche in which
specific hematopoietic lineage pathways are managed in proximity to a rich vascular
network. The bone and its osteoblasts, osteoclasts, and ''resting cells''are also contributors to
this microenvironment. Also present within this mix of cells are rare multipotent cells that can
differentiate along several mesenchymal lineage pathways, culminating in the formation of …