• Hanna Pisarek, Jolanta Kunert-Radek, Maciej Radek, Jacek Swietoslawski, Katarzyna Winczyk, and Marek Pawlikowski.
• Department of Neuroendocrinology, Medical University of Łódź, Poland.
• Neuroendocrinol Lett. 2011 Jan 1;32(1):96-101.

ObjectiveSurgical treatment of pituitary macroadenomas often fails because of tumor recurrence after the operation. The causes of tumor recurrence are complex, but one of them may be the high growth potential of the adenoma. As somatostatin receptors mediate antiproliferative, anti-angiogenic and pro-apoptotic actions, it seemed reasonable to investigate their expression in dependence on the adenoma recurrence.MethodsSamples of primary and recurrent gonadotropinomas excised surgically from patients were examined. This type of pituitary adenomas was chosen because of its relatively high recurrence rate. The adenoma phenotype and expression of somatostatin receptor subtypes 1-5 (SSTR 1-5) were investigated by immunohistochemistry, and the level of SSTR expression was semiquantitatively scored.ResultsIt was found that the adenomas undergoing the early recurrence have lower expression of SSTR 2A and 3 in comparison to those which did not recur during 5 years lasting observation. On the other hand, the recurrent tumors show higher expression of SSTR 1, 2A, 3 and 5 subtypes than their primary counterparts.ConclusionsIt is hypothesized that SSTR may, at least in part, counteract adenoma recurrence. On the other hand, it can be also presumed that the recurrent gonadotropinomas may be more sensitive to somatostatin analog treatment than primary ones. These hypotheses need to be confirmed in further studies.

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