Hematopoietic Stem Cell Niches in Hematological Disorders

Functions of hematopoietic stem cells (HSCs) required for the hematopoietic homeostasis are tightly regulated by their unique microenvironments (niches) in bone marrow. Previous studies have revealed that bone marrow mesenchymal stem cells are an essential player to keep HSCs quiescent that is a key behavior of stem cells to protect them from being exhausted and malignant transformation by exogenous insults. This article will review our studies and recent literature that argue about the contribution of bone marrow microenvironments altered with aging to the pathogenesis, clonal evolution and leukemic transformation in myelodysplastic syndrome (MDS).