Quantitative Techniques for Study of the Anatomy and Function of Small Blood Vessels in Tumors

Abstract

The staining technique described has facilitated recognition of small blood vessels in sections of a transplanted rat mammary tumor. The mean distance of cells from their nearest blood vessel in each of two tumors was estimated; this distance was significantly greater in the larger tumor and mitotic cells tended to be closer to blood vessels than interphase cells. Despite a high vascular density, widespread regions of necrosis were observed in larger tumors and there appeared to be intact blood vessels within these necrotic regions. A technique also is described in which part of the blood of a tumor-bearing animal was replaced by ⁵¹ Cr-labeled blood. This isotope gave high resolution autoradiographs, and a comparison of labeling indices of tumor and peripheral blood was used to estimate the proportion of tumor blood which did not exchange with that of the general circulation. In sections, few labeled red cells were observed within necrotic regions; thus cell death and necrosis were closely associated with stasis in tumor blood vessels.