"Caught in the net" - the extracellular matrix of the bone marrow in normal haematopoiesis and leukaemia.

Abstract The influence of the bone marrow microenvironment on normal haematopoiesis, but also leukaemia has largely been accepted. However, the focus has predominantly been on the role of various cell types or cytokines maintaining haematopoietic stem cells or protecting leukaemia stem cells from different therapies. A frequently overlooked component of the bone marrow microenvironment is the extracellular matrix which provides not just a mechanical scaffold, but which also serves as a source of growth factors. We discuss here how extracellular matrix proteins directly or indirectly modulate HSC physiology and influence leukaemia progression. It is to be hoped that existing and future studies on this topic may propel forward the possibility of augmenting normal haematopoiesis and improving therapies for leukaemia, for instance by targeting of the extracellular matrix in the bone marrow.