[Detection of minimal residual disease in children with neuroblastoma]

The presence of residual cells in bone marrow specimens of stage 4 patients, is an important prognostic parameter in neuroblastoma. Sensitive and specific standardized techniques are a prerequisite to detect and quantify these residual cells. In this respect, we evaluated an immunocytochemical test, a multiparameter flow cytometric assay and quantitative real-time RT-PCR. The latter technique was the most sensitive one in our hands. Although it is a simple and highly reproducible test, RT-PCR does not allow visualisation of neuroblastoma cells. On the contrary, the immunocytochemical APAAP assay is slightly less sensitive but can discriminate neuroblastoma cells morphologically. The combination of both assays seems to be ideal for monitoring residual cells in bone marrow of neuroblastoma patients. The flow cytometric multiparameter assay particularly offers additional information in GD2-negative neuroblastoma. Preliminary results of our study in children with stage 4 neuroblastoma reveals important information for the responsible physician and favours the prognostic role of minimal residual disease in neuroblastoma. Current multicenter trials in neuroblastoma trying to elucidate the relevance of residual cells at different time point during treatment are ongoing and will ultimately result in a consensus about this intruiging prognostic paramater.