Ploidy and proliferative index in medulloblastoma: useful prognostic factors?

Paraffin sections from 32 patients with primary medulloblastoma were analysed by flow cytometry for DNA ploidy and proliferative index to assess the value of these measurements in determining prognosis. Twenty-seven samples were informative. Of these 27 patients, 8 had had a total resection. The tumors were diploid in 13 patients and aneuploid in 14. Neither ploidy nor S-phase fraction were prognostic factors for survival, even when considered in conjunction with the type of surgery performed. This is in contrast to other published data, emphasising the need for large multicentre studies of biological prognostic factors in this rare tumour.