title: Expression of transmembrane protein tyrosine phosphatase gamma (PTPgamma) in normal and neoplastic human tissues.
abstract: OBJECTIVE
  To establish the conditions for protein tyrosine phosphatase gamma (PTPgamma) detection in paraffin tissues using two antibodies raised against its NH(2)- (anti-P4) and COOH-termini (gammaTL1); to analyse its expression in normal tissues and to perform an initial screening of neoplastic tissues.
  
  
  RESULTS
  Membranous and/or cytoplasmic PTPgamma expression was detected in the majority of epithelial cell types and in endocrine cells, with the highest expression in adrenal medulla, endocrine cells of the gastrointestinal tract and pancreatic islets. Both antibodies stained the thyroid follicular epithelium, but only anti-P4 antibody stained the colloid matrix, suggesting shedding/secretion of the PTPgamma extracellular domain. Marked loss of PTPgamma immunoreactivity was detected in subsets of ovarian (21%), breast (56%) and lung (80%) neoplasms. Conversely, cytoplasmic positivity was found in 37% of lymphomas, mainly of high-grade histotypes, while normal lymphocytes were negative. Brain tissue showed PTPgamma expression in a few neuronal and glial elements and PTPgamma was overexpressed in the majority of high-grade astrocytomas.
  
  
  CONCLUSIONS
  We have analysed PTPgamma expression in archival paraffin-embedded tissues for the first time, demonstrating particularly high expression in endocrine cells and both down- and up-regulation in neoplasia, the latter possibly reflecting the undifferentiated state of the neoplastic cells, suggesting a complex role for this phosphatase.
authors: Department of Pathology, University of Verona, Verona, Italy.
authors: M
authors: M
authors: Vezzalini
authors: A
authors: A
authors: Mombello
authors: F
authors: F
authors: Menestrina
authors: A
authors: A
authors: Mafficini
authors: M
authors: M
authors: Della Peruta
authors: C
authors: C
authors: van Niekerk
authors: M
authors: M
authors: Barbareschi
authors: A
authors: A
authors: Scarpa
authors: C
authors: C
authors: Sorio
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D015536:Down-Regulation; D004703:Endocrine System / Q000166:cytology / Q000201:enzymology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D008297:Male; D009369:Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000032:analysis; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011956:Receptors, Cell Surface; C516850:PTPRG protein, human; D017027:Protein Tyrosine Phosphatases; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5