QUANTITATIVE-ANALYSIS OF MICROVASCULAR CHANGES IN DIFFUSE ASTROCYTIC NEOPLASMS WITH INCREASING GRADE OF MALIGNANCY

Because glioblastoma multiforme (GBM) frequently shows striking; glome ruloid microvascular proliferation (MVP), this tumor has become a stro ng candidate for anti-angiogenic therapy However, the efficacy of anti -angiogenic treatment may rather be determined by the extent of classi c angiogenesis with the formation of delicate microvascular sprouts. T herefore, this study differentially quantifies the microvascular chang es in supratentorial diffuse astrocytic neoplasms by computerized imag e analysis of histological sections in which the microvessels were hig hlighted by a combined anti-collagen IV/MIB-1 staining. Four microvasc ular parameters (number, area, perimeter, diameter), the cellularity o f the glial tissue, and the MIB-1 labeling index were assessed in biop sies of astrocytoma (A, n = 13), anaplastic astrocytoma (AA, n = 14), and GEM (n = 20), and in normal cerebral cortex (n = 7) and white matt er (n = 7). In As and AAs, the microvascular parameters were not signi ficantly different from each other, and the microvascular changes were generally limited compared with WM and CX. In contrast, in GBMs the m icrovascular parameters were highly variable, and their overall mean v alue was significantly increased compared with As and AAs (ranging fro m 1.3x for vessel diameter to 3.3x for vessel area). Our study indicat es that not only glomeruloid MVP, but also classic angiogenesis, occur s mainly and only locally in GBMs. Thus, this study provides evidence that As and AAs are not good candidates for anti-angiogenic therapy. T he efficacy of such therapy for GBMs awaits further evaluation. Copyri ght (C) 1998 by W.B. Saunders Company.