Cytogenetic studies of pediatric brain and spinal cord tumors

Seventy pediatric patients with brain and spinal cord tumors had cytogenetic analysis of 99 samples of their tumors. Successful analysis was accomplished in 95%. Tumors included 43 gliomas, 9 medulloblastomas and a variety of other lesions. Forty-three patients had normal chromosomes; 28 of these had benign tumors and good outcomes. Of 11 patients with malignant tumors and normal chromosomes, 8 have no disease or stable disease during the period of follow-up. Outcomes of the 23 patients with abnormal chromosomes were poor; 17 had malignant pathology. Six patients with 'benign' disease and abnormal chromosomes died or have progressive disease. A relationship between outcome and pathologic diagnosis is often enhanced by cytogenetic findings. The study indicated specific chromosome abnormalities in certain pediatric brain tumors, such as chromosome 1 abnormalities in gliomas and isochromosome 17 abnormalities in medulloblastomas. It is recommended that cytogenetic studied be included in cooperative therapeutic trials. The clastogenic effects of treatment on the cytogenetic characteristics of tumors sequentially studied were demonstrated, as was the role of sampling variations. Attention to the treatment history of tumor samples, as well as evaluation of multiple samples from each tumor, may improve the reliability of cytogenetic studies.