Expression of vascular endothelial growth factor in growth hormone-secreting pituitary adenomas: special reference to the octreotide treatment

摘要

Objective: The present study was designed to investigate the localization of VEGF in GHsecretingnpituitary adenomas and to evaluate the characteristic differences of VEGF expression innrelation to the clinical effect of preoperative treatment with octreotide.nMethods: Fifty-six cases of GH-secreting adenomas, which were divided into three groups andnthree normal pituitary glands, were studied using immunohistochemistry for expression of VEGF.nThe octreotide group consisted of 33 patients who received the octreotide before the surgery.nThe bromocriptine group consisted of 11 patients who received bromocriptine orally. Thencontrol groups consisted of 12 patients who were not treated with octreotide or bromocriptinenpre-operatively. VEGF staining patterns for each specimen were examined under lightnmicroscopy and graded in a scale. These findings were correlated with clinical characteristics.nResults: VEGF was displayed in a diffuse cytoplasmic pattern in all cases. VEGF staining wasnstrongly seen in the cytoplasm in normal pituitary glands. Moderately positive staining withnVEGF appeared in six of 33 (18%) cases of the octreotide group, and in eight of 12 (67%) cases ofnthe control group. In contrast, weakly positive staining was observed in 25 of 33 (76%) cases ofnthe octreotide group, and in three of 12 (25%) cases of the control group. The staining patternndiffers statistically between the octreotide and control group, typically in densely granulated GHncell adenomas. Weak staining with VEGF appeared in all ten cases in which the tumor hadnshrunk. Age, gender, tumor size, tumor invasiveness and adenoma type did not influence VEGFnexpression.nConclusion: We conclude that octreotide may inhibit the angiogenesis through down-regulationnof VEGF. [Neurol Res 2008; 30: 518–522]