“…It can be divided between different types, based on their location: the endosteal niche, within the interior bone or on the endosteum surface, and the vascular/perivascular niche, mostly located in the medullary compartment of the BM. The native endosteal niche extracellular matrix (ECM) is mostly rigid, at 35-40 KPa, and comprises collagen (types I and IV), fibronectin, and osteopontin [95,96]. On the other hand, the vascular niche ECM, which surrounds all the different cells of this niche, is mostly compliant, at 0.1 to 0.3 KPa, comprising laminin, collagen type IV, and fibronectin, and is thus softer than the endosteal niche ECM [95,96].…”