Expression of cathepsin B and microvascular density increases with higher grade of astrocytomas.

Samples were taken from supratentorial gliomas border and normal brain autopsy which were divided into four groups, these including eight cases normal brain tissues, 30 cases of astrocytomas, 25 cases of anaplastic astrocytomas and 22 cases of glioblastomas. Cathepin B (CB) expression and microvessel density (MVD) were determined with immunohistochemical studies. Staining results of CB was scored according to the percentage of positive cells, graded as negative (-), weak (+), moderate (++), and strong (+ + +). MVD was analyzed by Weidner's revised technique. CB positive staining was negative in eight cases of normal brain tissue. Only 9 out of 30 cases of astrocytomas showed a low percentage of positive cells that were stained in a light, diffuse cytoplasmic pattern (score +). Twenty-two out of 35 cases of anaplastic astrocytomas showed positive light, granular staining pattern, it including five samples (score +), and 17 samples (score + +). In contrast, all 22 cases of glioblastomas were stained all, and it was present in a course, granular staining pattern with an intensity of score (+ +) of two sample, and score (+ + +) of 20 samples. Positive staining tumor cells were found in extracellular matrix (ECM), basement membrane (BM), and the endothelial cells of blood vessels were also positive stained. Along with elevating glioma grade, CB expression and MVD value were both increased. Therefore, it showed MVD value was positive correlated with expression of CB. It highly suggested that CB and angiogenesis plays an important role in glioma progression.