Expression of leukemia inhibitory factor in human pituitary adenomas: a morphologic and immunocytochemical study.
Leukemia inhibitory factor (LIF) is a pleiotropic, neuropoietic cytokine found in bovine, murine, and human fetal and adult pituitary cells, mostly in corticotrophs and somatotrophs. In addition, it has been found in a few GH- and ACTH-producing human pituitary adenomas. The aim of our study was to investigate the presence of LIF in various morphologic types of human pituitary adenomas. Ninety-eight operated pituitary adenomas diagnosed by light microscopy and classified by pituitary hormone immunocytochemistry and electron microscopy were studied. Sixty-eight tumors were functioning and included 15 densely granulated (DG) and 10 sparsely granulated (SG) somatotroph (SM) adenomas, 5 lactotroph (LT), 7 mixed SM-LT and 31 corticotroph (CRT) adenomas. The remaining 30 nonfunctioning tumors included 11 gonadotroph (GON) and 19 null cell (NULL) adenomas. For immunocytochemical demonstration of LIF, a specific polyclonal antiserum was applied on formalin-fixed, paraffin-embedded tissues. The immunohistoscore ranging from 1 to 64 grades was determined by multiplying the immunostaining grade (1-4) by the staining intensity grade (1-4), and by the heterogeneity grade (1-4). Ninety adenomas (92%) were variably immunopositive for LIF. LIF was expressed in 77.5% of CRT, 81.8% of GON, 93.3% of DG-SM, and in all SG-SM, LT, SM-LT and NULL adenomas. LT adenomas showed the highest immunostaining grade, followed by SG-SM, GON, NULL, SM-LT, DG-SM, LT and CRT adenomas. GON adenomas showed the highest immunohistoscore, followed by NULL, DG-SM, SM-LT, SG-SM, LT and CRT adenomas. Nonfunctioning tumors showed a significantly higher immunohistoscore compared to functioning adenomas (p < 0.01). We conclude that LIF expression is frequent in all types of functioning and nonfunctioning pituitary adenomas.
Kontogeorgos
G
G
Department of Pathology, G. Gennimatas Athens General Hospital, Greece. gkonto@cc.uoa.gr
Patralexis
H
H
Tran
A
A
Kovacs
K
K
Melmed
S
S
D000236:Adenoma / Q000145:classification / Q000378:metabolism* / Q000473:pathology*; D006056:Golgi Apparatus / Q000473:pathology; D006131:Growth Inhibitors / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines / Q000276:immunology / Q000378:metabolism*; D016612:Paraffin Embedding; D010911:Pituitary Neoplasms / Q000145:classification / Q000378:metabolism* / Q000473:pathology*
D006131:Growth Inhibitors; D015850:Interleukin-6; C507837:LIF protein, human; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines