ACTA ENDOCRINOLOGICA (BUC)

Introduction. Pituitary adenomas (PA) are the third most common intracranial tumors, with an incidence rate of 10-15%. More than half are invasive, infiltrating adjacent structures. The primary objective of this project was to determine whether MGMT expression is associated with the invasiveness of PA. Material and Method. All patients who underwent surgical decompression consecutively between 2007- 2012 were included. All data were obtained from the case records. Formalin-fixed paraffin-embedded (FFPE) tissue specimens were stained with hematoxylin and eosin (HE) and then examined via light microscope. Paraffin blocks that lacked necrosis and hemorrhage were chosen for histologic examination. In addition to an immunoprofile battery that consisted of Ki-67 and p53, MGMT, S-100 and Pan-CK were evaluated as well. Results. The subjects included 25 women and 15 men. The mean age was 48.9 ± 14.5 years. Of these, 63% of cases involved the invasion of adjacent structures. Of the PA, 17 (42%) were non-functioning pituitary adenomas (NFPA). There was a statistically significant relationship between the invasiveness and Ki-67, p53, MGMT expression, and prolactinoma. Gonodotropinomas were mostly non-invasive. FPAs presented invasive features more frequently than NFPAs. Pan-CK was positive in GH-secreting adenomas but negative in FSH- and LH-secreting adenomas. Conclusion. Ki-67 and p53 in lower expression level can be used for evaluating invasiveness but not for recurrence. MGMT expression can be a useful IHC indicator for invasiveness. However, Pan-CK cannot be used for invasiveness or aggressiveness.

Introduction. The pituitary gland serves as the center of the endocrine system. Stem cells are typically found in a specialized microenvironment of the tissue, called the niche, which regulates their maintenance, self-renewal, fate determination, and reaction to external influences. The aim of this study is to elucidate the role of stem cells in the initiation, invasion, and progression of pituitary adenomas. Materials and methods. All specimens were collected between January 2007 and April 2015. Radiological classification (invasiveness) for all cases was performed according to the Wilson-Hardy classification system. Immunohistochemical staining was performed to all specimens for CD133, Oct4, Sox2 and nestin. Results. The study included 48 patients. Of 48 patients, 17 (35.4%) were male and 31 (64.6%) were female. Mean age is 47.10±14.14 (17–86 yrs.). According to the Wilson-Hardy classification system, 27 (56.3%) were noninvasive adenomas. There was no statistical significance between the expression of pituitary stem cell markers (CD133, OCT4, SOX2, nestin) and invasiveness. Conclusion. All stem cell markers are stained extensively in pituitary adenomas, except for SOX2 which was stained weakly. However, there is no effect of stem cells on invasiveness of pituitary adenomas because we cannot find a difference of the staining level between invasive and non-invasive adenomas. Nestin was stained extensively in functional adenomas, especially for GH, PRL, and gonadotropin secreting adenomas. SOX2 was stained extensively for ACTH-secreting adenomas.