Immunohistochemical localization of glutathione S-transferase-pi in human colorectal polyps.
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.
Gaitanarou
Eleni
E
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.
Seretis
Eleni
E
Xinopoulos
Dimitrios
D
Paraskevas
Emmanuel
E
Arnoyiannaki
Niki
N
Voloudakis-Baltatzis
Irene
I
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
D051549:Glutathione S-Transferase pi