Evaluation of angiogenesis in 77 pituitary adenomas using endoglin as a marker

• Published in: Neuropathology 2009-02, Vol.29 (1), p.40-44
• Main Authors: Pizarro, Cristina B., Oliveira, Miriam C., Pereira-Lima, Julia F.S., Leães, Carolina G.S., Kramer, Carolina K., Schuch, Tiago, Barbosa-Coutinho, Lígia M., Ferreira, Nelson P.
• Format: Article
• Language: English
• Subjects: Adenoma - metabolism; Adenoma - pathology; Adenoma - secretion; Adult; Aging; Analysis of Variance; angiogenesis; Antibodies; Antibodies, Antinuclear; Antibodies, Monoclonal; Antigens, CD - analysis; Antigens, CD - immunology; CD 105; Cell Proliferation; Endoglin; Female; Humans; Immunohistochemistry; Male; MIB-1; microvascular density; Microvessels - metabolism; Microvessels - pathology; Middle Aged; Neovascularization, Pathologic - metabolism; Neovascularization, Pathologic - pathology; pituitary adenomas; Pituitary Hormones - secretion; Pituitary Neoplasms - metabolism; Pituitary Neoplasms - pathology; Pituitary Neoplasms - secretion; Receptors, Cell Surface - analysis; Receptors, Cell Surface - immunology; Sex Characteristics; Tumor Burden
• ISSN: 0919-6544; 1440-1789
• DOI: 10.1111/j.1440-1789.2008.00937.x

Angiogenesis, a fundamental process for the development and growth of a tumor, is less expressive in adenomas than in the normal pituitary tissue. There is controversy about the behavior of angiogenesis as a function of hormonal secretion or other characteristics of pituitary tumors. Endoglin (CD105) is a proliferation‐associated antigen on endothelial cells, as well as an endothelial progenitor cell marker. We used the anti‐endoglin antibody, a glycoprotein expressed in endothelial cells and conjunctive tissue, as a new marker particularly associated with neovascularization, in order to determine microvascular density (MVD) in pituitary adenomas. There were 77 samples, 31 males and 46 females, carriers of micro‐ (n = 24) or macroadenomas (n = 53). No significant difference was found in MVD concerning the variables of age, clinical presentation, and immunohistochemical phenotype or tumor size. MVD in males (median 5.4) was significantly higher (P = 0.001) than in females (median 3.0). Cell proliferation, as evaluated by the MIB‐1 antibody (a cellular proliferation index [Ki‐67 antigen], which is present in all stages of the cellular cycle except for the resting cells), ranged from 0% to 19.58%. No correlation was found between MIB‐1 and MVD. It is possible to infer that the lower MVD found in pituitary adenomas in females reflects an inhibitory estrogen action on TGF‐β1, a protein involved in vascular remodeling. Because of its role as a TGF receptor ligand, endoglin proved to be sensitive in detecting this gender difference in pituitary tumor angiogenesis.