title: Usefulness of immunological detection of the human telomerase reverse transcriptase.
abstract: OBJECTIVE
  Recent years have seen a considerable wealth of studies conducted on the potential usefulness of telomerase determination in diagnosis, prognosis and targeted cancer therapy. The frequently used Telomeric Repeat Amplification Protocol assay suffers from some drawbacks, the most important being the rate of false positives. In situ analysis using well characterised antibodies directed against the human telomerase reverse transcriptase (hTERT) would therefore appear to be important to morphologically identify the nature of telomerase positive cells.
  
  
  METHODS
  We performed immunostaining in a series of cultured cells and in normal, preneoplastic and tumour tissues from different organs using a monoclonal antibody directed against the catalytic subunit of telomerase.
  
  
  RESULTS
  Immunoreactivity was not observed in perennial cells of terminally differentiated cardiac and skeletal muscular tissues or in small pyramidal cells of the cerebral cortex. Conversely, it was found in other normal somatic tissues as well as in precancerous lesions and in all tumour histotypes.
  
  
  CONCLUSIONS
  Immunohistochemistry with a well characterised hTERT-specific monoclonal antibody permitted the identification of hTERT immunopositive cells in normal somatic tissues. Whether hTERT protein detected by immunostaining with hTERT-specific Tel 3 36-10 antibody is actually the degraded form of the protein that retains hTERT antigenicity but not enzymatic function, or whether it represents the real, potentially functional catalytic subunit of the enzyme, immunohistochemistry would not seem to represent a useful tool to investigate the role of telomerase and the mechanisms involved in its regulation.
authors.affiliation: Division of Oncology, Morgagni-Pierantoni Hospital, Forlì, Italy. a.volpi@ausl.fo.it
authors.forename: Annalisa
authors.initials: A
authors.lastname: Volpi
authors.forename: Sara
authors.initials: S
authors.lastname: Bravaccini
authors.forename: Laura
authors.initials: L
authors.lastname: Medri
authors.forename: Serenella
authors.initials: S
authors.lastname: Cerasoli
authors.forename: Michele
authors.initials: M
authors.lastname: Gaudio
authors.forename: Dino
authors.initials: D
authors.lastname: Amadori
mesh_terms: D001921:Brain / Q000473:pathology; D020134:Catalytic Domain; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics*; D005347:Fibroblasts / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D007158:Immunologic Techniques; D009369:Neoplasms / Q000378:metabolism*; D011379:Prognosis; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000378:metabolism; D019098:Telomerase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays; D001749:Urinary Bladder Neoplasms / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D019098:Telomerase