Galectin-3 Expression in Functioning and Silent ACTH-Producing Adenomas.
Galectin-3 (Gal-3), a beta galactoside-binding protein, has been implicated in a variety of biological functions including cell growth, differentiation, tumor cell adhesion, angiogenesis, tumor progression, and metastasis. We recently reported that Gal-3 was expressed in a subset of normal pituitary cells and tumors including PRL, ACTH, and in folliculo-stellate (FS) cells and tumors and that Gal-3 had an important regulatory role in pituitary cell proliferation. We further investigated the expression of Gal-3 protein in ACTH- and PRL-producing tumors and the expression of various galectin mRNAs by RT-PCR in pituitary adenomas and normal pituitary. Most silent ACTH subtypes 1 and 2 adenomas were negative or only focally positive for Gal-3 expression compared to functioning ACTH tumors from patients with Cushing's disease and Nelson's syndrome. In the normal pituitary, Gal-3 was expressed in less than 1% of the basophil-invading cells (ACTH cells present in the posterior pituitary) and in a subset of the anterior lobe ACTH-positive cells. RT-PCR analyses showed that many members of the galectin family including galectins 1, 2, 3, 4, 5, 6, 7, 8, and 9 were expressed in normal pituitary and in functioning ACTH- and PRL-producing tumors. These results indicate that Gal-3 is associated with functioning ACTH and PRL tumors and is expressed infrequently in silent ACTH adenomas, suggesting that Gal-3 protein and/or gene is altered in non-functioning ACTH tumors. The use of ACTH and Gal-3 immunostaining should help in the diagnosis of silent ACTH adenomas.
Jin
Long
L
Department of Pathology, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA.
Riss
Dominik
D
Ruebel
Katharina
K
Kajita
Sabine
S
Scheithauer
Bernd W
BW
Horvath
Eva
E
Kovacs
Kalman
K
Lloyd
Ricardo V
RV
D049913:ACTH-Secreting Pituitary Adenoma / Q000378:metabolism* / Q000473:pathology; D000236:Adenoma / Q000378:metabolism* / Q000473:pathology; D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000328:Adult; D015153:Blotting, Western; D005260:Female; D037502:Galectin 3 / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology; D011388:Prolactin / Q000378:metabolism; D015175:Prolactinoma / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D037502:Galectin 3; D012333:RNA, Messenger; D000324:Adrenocorticotropic Hormone; D011388:Prolactin