Microvessel density in pituitary adenomas and carcinomas

Abstract

Tumor growth depends on several factors, including angiogenesis. Tumors cannot grow if new vessels are not formed to supply the cells with oxygen and other nutrients and to remove waste products. Increased angiogenesis can be correlated with tumor growth and metastatic potential in many tumor types, indicating that neoformation of vessels is a prognostic indicator of tumor behavior. We evaluated microvessel densities in 157 various pituitary adenoma types and seven pituitary carcinomas using immunocytochemistry for CD-34 antigen, a reliable marker of endothelial cells. The lowest percentage of microvessel density was found in growth hormone-producing adenomas, the highest level in pituitary carcinomas. In general, no major correlation was found between MIB-1 index (an indicator of cell proliferation) and microvessel density. The statistical study also demonstrated no gender-dependent changes in the microvessel density of pituitary tumors. Although the microvessel density was not significantly different in relation to invasiveness of pituitary tumors, our results demonstrate a tendency of invasive pituitary tumors to be more highly vascularized than non-invasive ones. Dopamine agonist and long-acting somatostatin analog treatment compared with untreated tumors did not significantly affect microvessel densities. Statistical differences were demonstrated in the microvessel density of macroadenomas between patients older and patients younger than 40 years. Significant differences were also apparent in the microvessel densities between microadenomas and macroadenomas diagnosed in young patients but not in the older age group. The strongly positive correlation observed between microvessel density and age is consistent with the view that age of the host may have an influence on the extent of neovascularization of pituitary adenomas.

Cyclooxygenase‐2 expression in human pituitary tumors

“…18 The role of COX-2 in promoting metastasis relates to its activity as a tumor promoter by its stimulation of angiogenesis and metalloproteinase activity. 19,20 Although pituitary carcinomas are more vascularized than adenomas, 25 the occurrence of cerebrospinal metastases in these rare tumors suggests that hematogenous spread is not the exclusive domain of metastasis. This may explain partially a recent report that concluded that metalloproteinase activity in pituitary tumors does not correlate with metastatic potential.…”

“…Details of immunohistochemistry, including the duration of exposure and control procedures for these three stains, as well as the morphometric quantification method have been described in previous publications. 25,26,32,33 Most tumors (n ϭ 119) were fixed in glutaraldehyde, routinely processed, embedded in Epon-Araldite, and studied by transmission electron microscopy.…”

“…22,23 Because the histologic appearance of pituitary tumors is a poor predictor of aggressive behavior, 24 a number of studies have assessed cell proliferation and angiogenesis markers as predictors of tumor prognosis. [25][26][27][28][29] To obtain deeper insight into the role of COX-2 in pituitary tumor pathobiology, we analyzed the correlation between COX-2 expression and immunolabeling for MIB-1, a cell proliferation marker, as well as microvessel density (MVD), microvessel surface density (MSD), and expression of hypoxia-inducible factor-1␣ (HIF-1␣).…”

Angiogenesis in patients with craniopharyngiomas

“…[13][14][15][16][17]36,37 In addition, the assessment of MVD in a primary tumor ultimately may prove to be a significant and independent prognostic parameter related to tumor recurrence, metastasis, and overall patient survival. [37][38][39][40][41][42] The prognostic significance of angiogenesis has been confirmed in different types of brain tumors, e.g., diffuse astrocytomas of varying grade. In all of these tumors, angiogenesis correlates with tumor behavior and altered function of the blood-brain barrier.…”

Metastatic papillary craniopharyngioma: Case study and study of tumorangiogenesis

“…Both reactions were quanti ed in 29 randomly selected elds (6.7 mm 2 ) and expressed as the percentage of tumor area occupied by CD34-positive vessels (Vidal et al, 2001a), and the percentage of tumor tissue occupied by nucleated VEGFimmunoreactive cells. The latter was calculated as previously described (Vidal et al, 2001). In situ hybridization for VEGFR2 mRNA was carried out as previously described (Qian et al, 2001) using an oligonucleotide probe complementary to regions 309-318 of human mVEGFR2.…”