Growth activity of tumors at different intracranial structures: immunohistochemical study with bromodeoxyuridine.

To elucidate the environmental influence on the growth of a tumor, bromodeoxyuridine (BrdU) uptake in multiple tumor foci within the intracranial cavity was studied immunohistochemically with a monoclonal antibody. Walker 256 tumor implanted intracerebrally produced multifocal tumors presented as intraparenchymal solid tumor, tumor in the choroid plexus, and leptomeningeal dissemination. The BrdU-labeling indices, or the S-phase fractions (% of nuclei labeled by BrdU divided by the number of tumor cell nuclei scored; LI), of those tumors were 48.4 +/- 1.1, 59.1 +/- 1.3, and 27.9 +/- 5.9, respectively (mean +/- SEM). These differences in LI, or the tumor growth activity, are discussed in relation to the different environmental conditions in different host structures. These host structure-related modification of tumor growth would be important in evaluating the proliferative activity of tumors growing at various intracranial structures.