Expression of bcl-2 gene product in neuroblastoma.

The expression of bcl-2 is associated with inhibition of apoptosis and prolonged cell survival. The purpose of this study was to examine the immunoreactivity of neuroblastoma and ganglioneuroblastoma tissue samples to the bcl-2 gene product in order to see if it was related to prognosis. BCL-2 protein was detected in all the 46 formalin-fixed, paraffin-embedded samples from 34 patients representing all clinical stages and sites of involvement. Immunopositivity was observed in tumours from the primary and metastatic sites. Moreover, it was demonstrated in the pre-chemotherapy and the post-chemotherapy samples from six cases with stage 4 disease. It was observed in neuroblasts in various stages of differentiation. A small proportion of undifferentiated neuroblasts were negative. As BCL-2 oncoprotein was present in all the cases irrespective of the clinical outcome, it does not appear to be one of the factors influencing prognosis.