CD146+ bone marrow stromal cells have been recently recognized as clonogenic osteoprogenitors able to organize a complete hematopoietic microenvironment. In this study we used immunohistochemical analysis to investigate the contribution of CD146+ bone marrow osteoprogenitors to the stromal remodeling occurring in the different stages of primary myelofibrosis. We found that CD146+ cells sited at the abluminal side of the bone marrow vessels and branching among hematopoietic cells significantly increased in the advanced stages of primary myelofibrosis (p
