Immunohistochemical expression of pituitary tumor transforming gene (PTTG) in pituitary adenomas: a correlative study of tumor subtypes.
OBJECTIVE
We investigated the correlation between immunohistochemical expression of the pituitary tumor transforming gene (PTTG) and pituitary adenoma subtype.


METHODS
Pituitary adenomas (n = 89) were stained for PTTG using the streptavidin-biotin-peroxidase complex method and a monoclonal PTTG antibody.


RESULTS
PTTG staining was found to be cytoplasmic with a pronounced paranuclear expression pattern. Reactivity was highest in growth hormone (GH) adenomas as compared with other tumors, including prolactin (PRL), follicle-stimulating hormone/luteinizing hormone/alpha subunit, as well as adrenocorticotrophic hormone-secreting adenomas. PRL adenomas exhibited the lowest expression levels. Among GH adenomas, untreated tumors demonstrated significantly higher PTTG levels than octreotide-treated examples. Although dopamine agonist-treated PRL adenomas tended to show lower expression levels, statistical significance was not reached.


CONCLUSIONS
Our finding that PTTG was differentially expressed in pituitary adenoma subtypes suggests a cell-specific function for PTTG. Moreover, treatment of GH adenomas with somatostatin analogues lowered PTTG expression. Further investigation into mechanisms mediating cell-specific expression of PTTG is warranted.
Salehi
Fateme
F
St Michael's Hospital, University of Toronto, Toronto, ON, Canada. 8fs4@queensu.ca
Kovacs
Kalman
K
Scheithauer
Bernd W
BW
Cantelmi
David
D
Horvath
Eva
E
Lloyd
Ricardo V
RV
Cusimano
Michael
M
D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000378:metabolism; D001971:Bromocriptine / Q000627:therapeutic use; D006727:Hormone Antagonists / Q000627:therapeutic use; D006801:Humans; D007124:Immunoenzyme Techniques; D009363:Neoplasm Proteins / Q000378:metabolism*; D015282:Octreotide / Q000627:therapeutic use; D010911:Pituitary Neoplasms / Q000145:classification / Q000175:diagnosis / Q000378:metabolism*; D064249:Securin
D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; D006727:Hormone Antagonists; D009363:Neoplasm Proteins; D064249:Securin; C578002:pituitary tumor-transforming protein 1, human; D001971:Bromocriptine; D015282:Octreotide