<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>Nucleophosmin is a nucleolar phosphoprotein that is more abundant in tumor cells than in normal resting cells. Stimulation of the growth of normal cells, e.g., mitogen activation of B lymphocytes, is accompanied by an increase in nucleophosmin protein level. Although the function of nucleophosmin has not been defined precisely, ample evidence suggests that it is involved in the assembly of ribosomal proteins into ribosomes. Electron microscopic study indicates that nucleophosmin is concentrated in the granular region of the nucleolus, where ribosome assembly occurs. (from OMIM)</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition><n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A human nuclear matrix protein with demonstrated immunohistochemical staining differences between benign and malignant prostate tissue.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>