Immunohistochemical expression of nestin in the non-tumorous hypophysis and in pituitary neoplasms.
The aim of the present work was to investigate whether nestin, a member of the intermediate filament family, is immunohistochemically expressed in the non-tumoral human hypophysis and pituitary neoplasms. Twenty-three normal pituitaries and 125 pituitary neoplasms were included. The tissues were formalin-fixed and paraffin embedded. The neoplasms were identified on hematoxylin-eosin stained sections and were classified by immunohistochemistry as well as electron microscopy. For immunohistochemistry, the streptavidin-biotin-peroxidase complex method was applied using appropriate controls. Several corticotrophs in the autopsy obtained pituitaries showed cytoplasmic nestin immunopositivity. No nestin immunoreactivity was found in other cell types in non-tumorous adenohypophyses and in the cells of various pituitary adenomas. Nestin was, however, expressed in a small proportion of endothelial cells in both anterior and posterior lobes. Staining was also noted in several pituicytes, neurohypophysial nerve fibers, and Herring bodies. In contrast to CD-34 and Factor-8 immunostaining which demonstrated immunopositivity in practically all endothelial cells of every capillary, nestin expression was only focally seen suggesting that the functional status of the immunoreactive and non-staining endothelial cells was not the same. No statistically significant correlation was apparent between nestin immunoreactivity and patient age, gender, tumor size, mitotic index, Ki-67, labeling nuclear index, hormonal immunoprofile, and tumor type. In conclusion, nestin expression in adenomas cannot be viewed as a biologically relevant marker of cell proliferation and as a prognostic indicator. The patchy expression of nestin in endothelial cells remains unexplained and its significance requires further studies.
Rotondo
Fabio
F
Department of Laboratory Medicine, University of Toronto, St. Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8. rotondof@smh.toronto.on.ca
Kovacs
Kalman
K
Horvath
Eva
E
Bell
C David
CD
Lloyd
Ricardo V
RV
Scheithauer
Bernd W
BW
D000236:Adenoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D002648:Child; D005260:Female; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D064231:Nestin; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D011388:Prolactin / Q000378:metabolism
D014408:Biomarkers, Tumor; D007381:Intermediate Filament Proteins; C577484:NES protein, human; D009419:Nerve Tissue Proteins; D064231:Nestin; D011388:Prolactin