Expression of bcl-2 protein in nephroblastomas

Bcl-2 expression has been shown to relate to prognosis in several neoplasms. A study of 139 cases of nephroblastomas was undertaken to ascertain the prognostic value of bcl-2 immunoexpression. Archival formalin-fixed, paraffin-embedded tissue sections were stained with monoclonal anti-bcl-2 antibody using a peroxidase-labelled streptavidin biotin kit. 75.5% of cases showed bcl-2 immunoreactivity, however, heterogeneous staining was observed within each case. No statistically significant correlation was found when bcl-2 expression was compared to histology (P=0.451), disease status (P=0.375) and disease stage (P=0.875). A statistically significant difference in bcl-2 protein was noted when comparing tumours treated with and those not treated with pre-operative chemotherapy (P=0.002). Further analysis of the cases that were treated with pre-operative chemotherapy showed a striking difference in survival periods between bcl-2 positive (shorter) and negative tumours (longer). Although not statistically significant, we think that this finding requires further investigation in other series. The results of bcl-2 immunoexpression in nephroblastomas may have prognostic implications that impact on patient treatment protocols.