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Expression of transmembrane protein tyrosine phosphatase gamma (PTPγ) in normal and neoplastic human tissues
Author(s) -
Vezzalini M,
Mombello A,
Menestrina F,
Mafficini A,
Della Peruta M,
Van Niekerk C,
Barbareschi M,
Scarpa A,
Sorio C
Publication year - 2007
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/j.1365-2559.2007.02661.x
Subject(s) - biology , protein tyrosine phosphatase , pathology , epithelium , enteroendocrine cell , immunohistochemistry , adrenal medulla , antibody , extracellular matrix , endocrinology , tyrosine , endocrine system , microbiology and biotechnology , medicine , immunology , hormone , biochemistry , catecholamine
Aims: To establish the conditions for protein tyrosine phosphatase gamma (PTPγ) detection in paraffin tissues using two antibodies raised against its NH 2 ‐ (anti‐P4) and COOH‐termini (γTL1); to analyse its expression in normal tissues and to perform an initial screening of neoplastic tissues. Methods and results: Membranous and/or cytoplasmic PTPγ 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 PTPγ extracellular domain. Marked loss of PTPγ 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 PTPγ expression in a few neuronal and glial elements and PTPγ was overexpressed in the majority of high‐grade astrocytomas. Conclusions: We have analysed PTPγ 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.