title: Expression of nucleophosmin/B23 in normal and neoplastic colorectal mucosa.
abstract: Nucleophosmin/B23 is a 38 kD molecular phosphoprotein involved in ribosome assembly and transport. In view of the fact that nucleophosmin/B23 appears to be more abundant in tumour cells than in normal cells, the mRNA expression and immunohistochemical localization of nucleophosmin/B23 were investigated in 19 samples of non-neoplastic mucosa, six adenomas, and 16 adenocarcinomas of the colorectum. Northern blot analysis revealed that nucleophosmin/B23 mRNA is expressed at a higher level in adenomas and carcinomas than in non-neoplastic mucosa of the colorectum. Immunohistochemical staining of formalin-fixed, paraffin-embedded tissue sections after microwave antigen retrieval, using a nucleophosmin/B23-specific monoclonal antibody, showed almost exclusively diffuse nuclear reactivity of a majority of the epithelial cells in non-neoplastic mucosa: in adenomas, reactivity was almost exclusively nucleolar and in carcinomas, nuclear as well as nucleolar staining was observed. During mitosis, the immunoreactivity of nucleophosmin/B23 appears in the cytoplasm. The results indicate that the expression of nucleophosmin/B23 is higher in neoplastic than in non-neoplastic colorectal mucosa. Furthermore, the pattern of nucleophosmin/B23 expression shifts from nuclear to nucleolar early in the adenoma-carcinoma sequence. The exact function of nucleophosmin/B23 in colorectal carcinogenesis remains to be determined.
authors.affiliation: Department of Pathology, Erasmus University Rotterdam, The Netherlands.
authors.forename: Y
authors.initials: Y
authors.lastname: Nozawa
authors.forename: N
authors.initials: N
authors.lastname: Van Belzen
authors.forename: A C
authors.initials: AC
authors.lastname: Van der Made
authors.forename: W N
authors.initials: WN
authors.lastname: Dinjens
authors.forename: F T
authors.initials: FT
authors.lastname: Bosman
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism; D000236:Adenoma / Q000378:metabolism; D015152:Blotting, Northern; D015179:Colorectal Neoplasms / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D007124:Immunoenzyme Techniques; D007413:Intestinal Mucosa / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D000090243:Nucleophosmin; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics
chemical_list: C000716967:NPM1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D000090243:Nucleophosmin