Both isoforms are expressed on the cell surface. CD34-T/CD34-F ratio increases with cell differentiation,developmental stage:On early hematopoietic progenitor cells.,disease:Abnormal CD34 expression in leukemogenesis.,function:Possible adhesion molecule with a role in early hematopoiesis by mediating the attachment of stem cells to the bone marrow extracellular matrix or directly to stromal cells. Could act as a scaffold for the attachment of lineage specific glycans, allowing stem cells to bind to lectins expressed by stromal cells or other marrow components. Presents carbohydrate ligands to selectins.,online information:CD34 entry,PTM:Highly glycosylated.,PTM:Phosphorylated on serine residues by PKC.,similarity:Belongs to the CD34 family.,tissue specificity:Selectively expressed on hematopoietic progenitor cells and the small vessel endothelium of a variety of tissues.,