PROCEEDINGS |
This study was conducted to evaluate by morphometry the vascularity of tumors growing in the brain of nude mice. Microvessel density (MVD), size of vessels and distance of tumor cells from the nearest vessels were measured. Three human and three murine tumors were injected into the carotid artery of nude mice. The animals were sacrificed when they were moribund and the brains were snap frozen in liquid nitrogen. Some animals were injected with bromodeoxyuridine (BrdU) 1 hour before necropsy. Cyrosections were immunostained for CD31 and BrdU. Morphometry was performed in the tumor and surrounding uninvolved tissues. Proximity of tumor cells to endothelial cells was measured in sections that were previously stained for BrdU and CD31 using a Euclidean distance map (Image Processing Tool Kit by J.C. Russ and J.C. Russ). We found that there were no "hot spots" in MVD in the brain metastasis but blood vessels in the tumor were generally larger than vessels in the adjacent area, and there is an inverse correlation between MVD and size of tumor vessels. The mean distance of tumor cells from vessels is inversely proportional to MVD and is dependent on tumor type. We conclude that in the absence of hot spots, size of vessels and proximity of tumor cells to vessels may be used to evaluate the tumor.