title: Immunohistochemical localization of glutathione S-transferase-pi in human colorectal polyps.
abstract: OBJECTIVE
  To investigate the distribution of the placental form of glutathione-S-transferase (GST) in colon polyps in order to evaluate the role of GST-pi in these tissues.
  
  
  METHODS
  Sixteen polyp tissues removed at colonoscopy were examined. Tissues were investigated histologically and ultrastructurally. GST-pi expression was also analysed immunohistochemically, using peroxidase anti-peroxidase (PAP) method and immunogold labelling method, for light and electron microscope respectively.
  
  
  RESULTS
  All polyp tissues examined were adenoma of low, mild and high- grade dysplasia as shown in the histopathological reports. Nevertheless, the examination of the above specimens with electron microscope revealed that 3 of 9 adenoma of mild dysplasia had ultrastuctural features similar to high-grade dysplasia adenoma. GST-pi was variably expressed in adenoma, with the lowest relative levels occurring in low-grade adenoma and the highest levels found in high-grade adenoma. GST-pi was located mainly in undifferentiated epithelial cells. GST-pi positive particles were found in the cytoplasm and especially in the nucleus adjacent to the nuclear membrane of these cells.
  
  
  CONCLUSIONS
  The overexpression of GST-pi in mild-grade adenomas with significant subcellular changes and in the majority of high-grade dysplasia adenoma suggests that this might be related to the carcinogenetic proceeding. Immunohistochemical localization of GST-pi in combination with ultrastructural changes indicate that GST-pi might be a sensitive agent for the detection of preneoplastic transformations in adenoma.
authors.affiliation: Department of Cell Biology, Electron Microscopy and Molecular Biology, "G. Papanicolaou" Research Center of Oncology and Experimental Surgery "Agios Savvas" Anticancer Hospital, 171, Alexandras Av., Athens 11522, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Gaitanarou
authors.forename: Eleni
authors.initials: E
authors.lastname: Seretis
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Xinopoulos
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Paraskevas
authors.forename: Niki
authors.initials: N
authors.lastname: Arnoyiannaki
authors.forename: Irene
authors.initials: I
authors.lastname: Voloudakis-Baltatzis
mesh_terms: D000236:Adenoma / Q000201:enzymology; D003110:Colonic Neoplasms / Q000201:enzymology; D003111:Colonic Polyps / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D051549:Glutathione S-Transferase pi / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron
chemical_list: D051549:Glutathione S-Transferase pi