Effects of medical treatment on proliferation parameters MIB-1 and topoisomerase-II[alpha] in GH secreting pituitary adenomas

S. Schlaffer; F. Lin; W. Saeger; M. Buchfelder

P1425

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Endocrine Abstracts (2012) 29 P1425

ICEECE2012 Poster Presentations Pituitary Clinical (183 abstracts)

Effects of medical treatment on proliferation parameters MIB-1 and topoisomerase-IIα in GH secreting pituitary adenomas

S. Schlaffer ¹ , F. Lin ¹ , W. Saeger ² & M. Buchfelder ¹

Err

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¹University Hospital Erlangen, Erlangen, Germany; ²Marienkrankenhaus, Hamburg, Germany.

Introduction: In this present study, we assessed the effects of the last preoperative medical treatment (dopamine-agonists, somatostatin-analogous and GH receptor antagonists) on the proliferation parameters Ki-67 and Topoisomerase-IIα in pituitary adenomas of patients with acromegaly.

Material and methods:: We retrospectively studied the clinical characteristics, neuroimaging, histology and immuno-histochemistry (Ki-67 and topoisomerase-IIα labelling index) of 365 specimens of GH expressing pituitary adenomas collected between 2002 and 2010. According to the last medical treatments before surgery, these cases were divided into five groups: no medication, dopamine agonist, somatostatin analogues, combination of both or GH receptor antagonist.

Results:: As compared with adenomas which had no medical treatment, the group of somatostatin analogues treated tumours as well as those who have been treated with GH-receptor antagonists showed significant lower values of Ki-67- and topoisomerase-IIα -labelling index (P<0.001, P=0.001 respectively), while the other groups showed no significant difference. However, no significant correlation was found between the dosages or the duration of the medical treatment. In the group of macro- and invasive adenomas higher values of both proliferation parameters were observed as compared with microadenomas (P<0.001) or non-invasive adenomas (P<0.001, P=0.001 respectively).

Conclusions:: Interestingly in this analysis as well as somatostatin-analogue and GH-receptor antagonist treatment is associated with a lower proliferation profile in GH secreting adenomas instead of the supported idea that peripheral GH-receptor blockade might lead to an increased tumour proliferation. From our point of view the reduced proliferation indices in the GH receptor group is the result of the previous attempt of somatostatin-analogue treatment which failed to control GH-secretion and therefore patients were put on GH-receptor antagonists.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.