CDCP1, also known as CUB domain-containing protein 1 isoform 1, is a transmembrane protein containing three extracellular CUB domains. This protein is involved in cell adhesion and cell matrix association. Also, CDCP1 may play a role in the regulation of anchorage versus migration or proliferation versus differentiation via its phosphorylation and may be a novel marker for leukemia diagnosis and for immature hematopoietic stem cell subsets. The extracellular region of human CDCP1 shares amino acid identity sequence with that of the mouse protein. Recombinant human CDCP1, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.