The role and clinical implications of the endosteal niche and osteoblasts in regulating leukemia.

Osteoblasts are one among the critical components of the endosteal bone marrow (BM) niche. In addition to hematopoietic stem cell fate, their role in leukemogenesis as well as metastasis of a variety of cancers has been demonstrated in various studies. In this regard, endosteal niche can have a dual role as an initiator and protective role against leukemia. Knowledge of growth factors, chemokines and cytokines secreted by osteoblasts as well as their interaction with signaling pathways inform our understanding of the development, prognosis, recurrence and treatment of malignant BM diseases. Clinical progress in targeting the endosteal niche is also discussed.