Survivin expression in childhood medulloblastomas: a possible diagnostic and prognostic marker.

Survivin is a member of the inhibitor of apoptosis gene family that is expressed in embryonic tissues during human ontogenesis and most human malignancies, but it is not present in the majority of normal adult tissues. Survivin is also a chromosomal passenger protein required for physiological cell divison. Survivin blocks apoptosis, via its BIR domain, by either directly or indirectly blocking the function of the members of the caspase cascade. The expression of this apoptosis inhibitor protein in medulloblastomas (MEDs) was examined for the first time. During the immunohistochemical study, a sensitive, four-step, alkaline phosphatase conjugated antigen detection technique was employed. The results did, in fact, demonstrate the presence of survivin in 10 to 50 per cent of medulloblastoma (MED) cells with medium intensity immunoreactivity (++, B) in this neuroectodermal brain tumor. These results indicate that survivin is probably not only a diagnostic marker, but also an important prognostic marker for MEDs/PNETs and may be useful in the future grading of malignancy in MEDs, much as grading is done today for astrocytomas (ASTRs). Furthermore, the almost exclusive neoplastic expression of survivin will allow development of new antineoplastic, immunotherapeutic strategies.