Characterization of solid tumor microvasculature: a three-dimensional analysis using the polymer casting technique.

Using a polymer casting technique in conjunction with scanning electron microscopy, the three-dimensional characterization of tumor microvasculature as a function of age of renal adenocarcinoma in the rat kidney is undertaken. The microvasculature of the rat tumor model is compared with VX2 carcinoma in the rabbit leg muscle. Light microscopy and transmission electron microscopy on the rat tumor model are performed to correlate the features seen under scanning electron microscopy of vascular casts. The casts show marked differences between tumor and normal microvasculature. The tumor vascular architecture appears disarrayed with prevalent atypical features such as coils, ribbons, sheets, dense capillary networks, saccular dilatations, leaky and otherwise highly irregular vessels. Sprouts of new growth capillaries are seen throughout the tumor casts. Compressed vessels are present and become more pronounced in older tumors. These features are not observed in normal controls treated under identical conditions. The application of this high resolution three-dimensional casting technique to tumor studies is promising for research in basic tumor mechanics as well as in the effects of tumor vasculature on mediating radiation and chemotherapy and the fundamental mechanisms of metastasis.