Pediatric medulloblastoma: prognostic value of p53, bcl-2, Mib-1, and microvessel density

The aim of this study was to retrospectively assess the prognostic value of p53 and bcl-2 protein expression, cell proliferation index (Mib-1 index), and tumor microvessel density (factor VIII-related antigen) in pediatric me dulloblastoma patients. Tumor specimens of 55 patients (age 2-18 years) wit h medulloblastoma treated with a curative intent between 1972 and 1991 were studied. Slides of paraffin embedded tissue were stained with monoclonal a ntibodies (mAb) and examined under high power light microscopy for the pres ence of immunoreactivity. Microvessel density was scored both in the area o f most intense staining ('Angio-max') and in 3 additional randomly selected areas. The sum of these 4 scores was termed 'Angio-total'. 'Annio-max' and 'Angio-total' were evaluated separately by two independent investigators t o assess reproducibility. None of the parameters studied, i.e, p53 or bcl-2 expression, Mib-1 index or microvessel density scores were associated with patient survival. Microvessel scores between observers were significantly but weakly correlated, with correlation coefficients (r) < 0.5 for both 'An gio-max' and 'Angio-total'. Leptomeningeal spread at diagnosis was the only independent factor associated with a poor survival (p = 0.003). There was no association of leptomeningeal metastasis with any of the biological mark ers tested in this study.