[Microvascular architecture of human gastrointestinal and breast cancer xenografts in nude mice, and its relation to chemosensitivity].

As a tumor factor possibly responsible for chemosensitivity of human cancer xenografts in nude mice, the vascular architecture of tumors growing in mice was investigated in 15 kinds of cancer lines. These consisted of 7 gastric, 3 colorectal, 3 breast and 2 pancreatic cancers. Whole body angiograms of tumor-bearing mice were obtained by perfusing a radiopaque silicone rubber compound (Microfil) through the left ventricle of each mouse. Each cancer retained a characteristic vascular architecture comparable to its histopathological finding. According to the vascularity of the viable part of the tumor, the 15 lines of cancer were classified into 5 groups. Compared with colorectal cancers, stomach cancers had a tendency to decline to a more hypervascular group. There was no apparent relation between vascularity and growth rate, or histological differentiation of the tumors. Among 14 anticancer agents studied, statistically significant correlation between chemosensitivity and vascularity of the 15 cancer lines was observed in 2 drugs, 5'-DFUR and adriamycin. The vascular architecture of the tumors would have some influence in their chemosensitivity through drug accessibility to cancer cells.