title: Enhanced nestin expression and small blood vessels in human pituitary adenomas.
abstract: The role of angiogenesis in human pituitary tumor progression is questioned. Our aim was to characterize the morphologic changes that occur in the vasculature of pituitary adenomas, in correlation with the expression of nestin, a protein found in endothelial cells of newly formed vessels of developing organs. We also evaluated the relation of angiogenic markers and nestin with Ki-67 index. Immunohistochemical studies were performed on paraffin embedded samples of 47 pituitary adenomas and six normal pituitaries. We determined microvessel density (number of CD31+ or CD34+ vessels per square millimetre), vascular area (cumulative area occupied by vessels), average vessel size, and further classified vessels as small (< 100 μm2) or large (> 100 μm2). We correlated the above parameters with nestin expression and Ki-67 index. Lower vascular area compared to normal tissue was found in adenomas (p < 0.05). Interestingly, pituitary adenomas had significantly more small vessels than control pituitaries (p < 0.04 for CD31 and CD34). In tumors many capillaries were positive for nestin, while scarce staining was detected in controls, so that nestin positive area was significantly higher in tumors. Furthermore, nestin area correlated positively with the % of small vessels. Ki-67 correlated neither with vascular area nor with nestin expression. In human pituitary tumors there was a predominance of small capillaries in correlation with increased expression of the progenitor marker nestin. We suggest that angiogenesis is an active process in these tumors, in spite of their low total vascular area when compared to normal pituitaries.
authors.affiliation: Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.
authors.forename: María Inés
authors.initials: MI
authors.lastname: Perez-Millan
authors.forename: Silvia Inés
authors.initials: SI
authors.lastname: Berner
authors.forename: Guillermina María
authors.initials: GM
authors.lastname: Luque
authors.forename: Cristian
authors.initials: C
authors.lastname: De Bonis
authors.forename: Gustavo
authors.initials: G
authors.lastname: Sevlever
authors.forename: Damasia
authors.initials: D
authors.lastname: Becu-Villalobos
authors.forename: Carolina
authors.initials: C
authors.lastname: Cristina
mesh_terms: D000236:Adenoma / Q000378:metabolism*; D000328:Adult; D000368:Aged; D001808:Blood Vessels / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D019394:Ki-67 Antigen / Q000378:metabolism; D008875:Middle Aged; D009389:Neovascularization, Pathologic; D064231:Nestin / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism*; D055815:Young Adult
chemical_list: D019394:Ki-67 Antigen; D064231:Nestin