| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2005: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2003: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2002: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
A detailed knowledge of the vascular system of tumors is requisite to a clear understanding of tumor physiology and pathology. In this study examination was made of the vascular architecture of rat mammary adeno carcinoma, rat fibrosarcoma, dog liver tumor, dog hepatoma, dog melanoma and Chinese hamster hepatoma. Vascular changes at various stages of growth of these tumors were investigated using histology, immunohistochemistry and scanning electron microscopy (SEM) of corrosion casts. In the early stage of tumor growth, capillaries within the neoplasms were thin with 8-10μm diameter, and were characterized by rows of vascular sprouts representing extensive neovascularization. In the intermediate stage, the growing tumor was multi-nodular and tumor cells were arranged in a tubulopapillary pattern. Capillaries formed spheroid vascular capsules and were characterized by dilation, to a diameter of 10-80μm, and blind ends. In the late stage of tumor growth, a remarkable reduction in the number of VEGF-positive cells and Ki-67-stained nuclei was demonstrated. Many arteriovenous anastomoses between the major arteries and veins were found in regions just before their entry to the tumor. The central regions of the tumor were degenerative and necrotic, and vasculature was confined to surface regions of the tumor, forming a basket-like configuration around the avascular central regions. We concluded that these microvascular alterations might change the homogeneity of tumor perfusion and contribute to necrosis in central portions of the tumor.
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