Human monocytic leukemia cell line THP-1 has been identified as a highly reproducible model for the differentiation of immature DCs (iDCs) and mature DCs (mDCs) in terms of phenotypic, morphologic and functional properties of DCs generated from CD14+ monocytes or CD34+ HPCs [30], [31] and it has been prove to function as an extremely powerful tool to investigate human DCs’ differentiation and maturation processes. The gene discussed is CD34; the disease is monocytic leukemia.