Endoglin and CD-34 immunoreactivity in the assessment of microvessel density in normal pituitary and adenoma subtypes.
Vascularization is a prerequisite of tumor growth, invasion and metastasis. In the present work, microvessel density was assessed by quantitating using two different endothelial cell biomarkers, endoglin (CD-105) and CD-34. Fifty endocrinologically active and 36 clinically nonfunctioning pituitary adenomas, all surgically resected, as well as 10 autopsy-derived normal adenohypophyses were investigated by immunohistochemistry. The results showed that in every pituitary adenoma type endoglin, an assumed biomarker of proliferating endothelial cells, immunostained fewer vessels than CD-34 which revealed immunopositivity in all capillaries. Differences in endoglin versus CD-34 immunoexpression indicate varying degrees of vascularity in pituitary adenoma subtypes. The low levels of endoglin immunoexpression in pituitary tumors exposed to long-acting somatostatin analogs and dopamine agonists are consistent with the view that these agents inhibit angiogenesis.


BACKGROUND
immunohistochemistry, endoglin, CD34, microvascular density, angiogenesis, pituitary.
Rotondo
F
F
Department of Laboratory Medicine, University of Toronto, Toronto, ON, Canada. rotondof@smh.ca
Sharma
S
S
Scheithauer
B W
BW
Horvath
E
E
Syro
L V
LV
Cusimano
M
M
Nassiri
F
F
Yousef
G M
GM
Kovacs
K
K
D000236:Adenoma / Q000098:blood supply* / Q000737:chemistry; D015703:Antigens, CD / Q000032:analysis*; D018952:Antigens, CD34 / Q000032:analysis*; D000071063:Endoglin; D006801:Humans; D007150:Immunohistochemistry; D055806:Microvessels / Q000737:chemistry; D010902:Pituitary Gland / Q000098:blood supply*; D010911:Pituitary Neoplasms / Q000098:blood supply* / Q000737:chemistry; D011956:Receptors, Cell Surface / Q000032:analysis*
D015703:Antigens, CD; D018952:Antigens, CD34; C064206:ENG protein, human; D000071063:Endoglin; D011956:Receptors, Cell Surface