Expression of p53 protein in pituitary adenomas

• Published in: Brazilian journal of medical and biological research Vol. 35; no. 5; pp. 561 - 565
• Main Authors: Oliveira, M C, Marroni, C P, Pizarro, C B, Pereira-Lima, J F, Barbosa-Coutinho, L M, Ferreira, N P
• Format: Journal Article
• Language: English
• Published: Brazil Associação Brasileira de Divulgação Científica 01.05.2002
• Subjects: Adenoma - chemistry; Adenoma - metabolism; Adolescent; Adrenocorticotropic Hormone - metabolism; Adult; Aged; BIOLOGY; Biomarkers, Tumor; Female; Growth Hormone - metabolism; Humans; Immunohistochemistry; Invasive adenoma; Male; MEDICINE, RESEARCH & EXPERIMENTAL; Middle Aged; Mutation; Neoplasm Invasiveness; p53; Pituitary; Pituitary adenoma; Pituitary Neoplasms - chemistry; Pituitary Neoplasms - metabolism; Prognosis; Prolactin - metabolism; Tumor Suppressor Protein p53 - analysis; Tumor Suppressor Protein p53 - genetics; Tumor Suppressor Protein p53 - metabolism; Immunohistochemistry; Invasive adenoma; Pituitary; Pituitary adenoma; p53
• ISSN: 0100-879X; 1414-431X; 0100-879X; 0034-7310
• DOI: 10.1590/S0100-879X2002000500008

Inactivating mutations of TP53, a tumor suppressor gene, are associated with abnormal cell proliferation. Although p53 expression is common in many human malignancies, p53 protein has seldom been evaluated in pituitary tumors. When detected, the percentage of p53-positive cells is low, and, in general, it is exclusive for invasive lesions. The aim of the present study was to use immunohistochemistry to determine the presence of p53 protein in pituitary adenomas from tumor samples of 163 surgeries performed in 148 patients (40% male, 60% female). In 35% of the cases the adenoma was nonfunctional, while in the others it was associated with PRL, GH and/or ACTH endocrine hypersecretion syndrome. Macroadenomas were observed in 83.2% of the cases with available neuroimage evaluation, of which 28% invaded the cavernous, sphenoid and/or ethmoidal sinus, bone, third ventricle or subfrontal lobe. p53 protein was detected in 2/148 patients (1.3%). Immunohistochemistry was positive for PRL and GH in these cases. Due to the high percentage of invasive pituitary adenomas found in our study, the low frequency of p53 detection suggests that it is inadequate as a routine marker for aggressiveness and as a predictive factor of tumor behavior.