CD90 is a GPI-anchored, developmentally regulated protein involved in various signaling cascades that mediate neurite outgrowth, T cell activation, tumor suppression, apoptosis, and fibrosis. It is a phosphatidyl-anchored cell surface glycoprotein which, when coexpressed with CD34 on cells from normal human bone marrow, identifies a subpopulation that includes putative hematopoietic, pleuripotent stem cells. CD90 is epigenetically regulated, or deregulated in some disease states, such as pulmonary fibrosis. The potentially reversible hypermethylation of the CD90 promoter offers the possibility of novel therapeutic options in this disease.
