Expression of nucleophosmin/B23 in normal and neoplastic colorectal mucosa

J Pathol. 1996 Jan;178(1):48-52. doi: 10.1002/(SICI)1096-9896(199601)178:1<48::AID-PATH432>3.0.CO;2-Y.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / metabolism
  • Adenoma / metabolism
  • Blotting, Northern
  • Colorectal Neoplasms / metabolism*
  • Gene Expression
  • Humans
  • Immunoenzyme Techniques
  • Intestinal Mucosa / metabolism*
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • RNA, Messenger / genetics
  • RNA, Neoplasm / genetics


  • Neoplasm Proteins
  • Nuclear Proteins
  • RNA, Messenger
  • RNA, Neoplasm
  • nucleophosmin