Tumor Angiogenesis: A Quantitative Method for Histologic Grading<xref ref-type="fn" rid="FN2">2</xref>

A quantitative technique for measuring the degree of angiogenesis in tumors is described. The microscopic angiogenesis grading system was based on 3 parameters of endothelial regeneration: vasopro-liferation, endothelial cell hyperplasia, and endothelial cytology, providing a composite rating of 0–100. The method was tested in grading the degree of neovascularization in cerebral neoplasms and vascular tissues induced by tumors and tumor extracts; it appeared to give quantitatively reproducible and biologically reasonable results. Preliminary observations on a variety of other tumors suggest that solid neoplasms can be classified according to the extent of angiogenesis along a spectrum ranging from the "endothelial-poor" tumors, such as the chondrosarcomas, to the "endothelial-rich" tumors, such as glioblastomas.