CD146+ bone marrow osteoprogenitors increase in the advanced stages of primary myelofibrosis

1 Department of Human Pathology, Paolo Giaccone University Hospital, University of Palermo, Palermo 2 Pathology Unit, Department of Medicine, Surgery and Odontology, San Paolo Hospital, and "Policlinico IRCCS" Hospital, Mangiagalli and Regina Elena Foundation, University of Milan 3 Department of Surgical Pathology, University of Pavia Medical School, IRCCS Policlinico San Matteo Foundation, Pavia 4 Haematology Unit, Department of Oncology and Haematology, Paolo Giaccone University Hospital, University of Palermo, Italy Correspondence: Claudio Tripodo, MD, Department of Human Pathology, University of Palermo, via del Vespro 129, 90127, Palermo, Italy. E-mail: tripodo{at}unipa.it 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