The erythropoietin receptor (EPOR) is a member of the cytokine receptor family. There are several isoforms including: EPOR-F (full length), EPOR-S (soluble form), and EPOR-T (truncated form). Upon erythropoietin (EPO) binding, the EPOR activates Jak2 tyrosine kinase which activates different intracellular pathways including: Ras/MAP kinase, phosphatidylinositol 3-kinase and STAT transcription factors. The stimulated EPOR appears to have a role in erythroid cell survival. Defects in the EPOR m