Pediatric central nervous system tumors: a cell kinetic study with bromodeoxyuridine.

Bromodeoxyuridine (BrdU), 150 to 200 mg/m2, was administered at the time of operation to 20 pediatric patients with neuroectodermal tumors to label tumor cells in the S phase. Immunocytochemical techniques were used on excised tumor specimens to detect cells containing BrdU, and the BrdU labeling index (LI) was calculated as the number of BrdU-labeled cells divided by the total number of cells counted. Four medulloblastomas, three glioblastomas multiforme, and two highly anaplastic astrocytomas had average BrdU LIs of 13.0 +/- 3.0% (SE), 12.7 +/- 4.3%, and 14.6 +/- 6.7%, respectively. Three of nine moderately anaplastic astrocytomas had BrdU LIs of greater than 1% (average, 6.5 +/- 2.4%), whereas six had LIs of less than 1%. In two juvenile pilocytic astrocytomas, which are considered slow-growing, the BrdU LIs were unexpectedly high, averaging 6.5 +/- 1.4%. Thus pediatric medulloblastomas, glioblastomas multiforme, highly anaplastic astrocytomas, and a minority of moderately anaplastic astrocytomas had high proliferative potentials, whereas most of the moderately anaplastic astrocytomas had low proliferative potentials. Although the number of cases in this study is still too small to yield statistically significant comparisons, the results indicate that some pediatric tumors have considerably higher LIs than histologically similar adult tumors studied previously.