Detection of metastatic neuroblastoma in bone marrow biopsy specimens with an antibody to neuron-specific enolase

To verify the practical utility of immunohistochemical analysis of bone marrow biopsy specimens in patients with neuroblastoma, we compared the results of routine histologic examination of 68 specimens with the results of immunohistochemical detection of tumor cells using an antibody to neuron-specific enolase (NSE). A commercially available polyclonal antibody to this enolase isoform consistently reacted with the neoplastic cells in biopsy specimens with histologic features diagnostic of (24 specimens) or suspicious for (one specimen) metastatic neuroblastoma. Immunohistochemical double-staining techniques documented that the NSE-positive neoplastic cells also reacted with antibodies to chromogranin and synaptophysin. Notably, anti-NSE detected small foci of metastatic neuroblastoma in two of 43 biopsy specimens that showed no evidence of metastatic tumor in the initial histologic sections. Rare NSE-reactive hematopoietic cells were present in approximately a third of the specimens with and those without neuroblastoma and were easily distinguished from metastatic tumor by morphologic examination. We conclude that this antibody to NSE consistently detects neuroblastoma cells in routinely processed bone marrow specimens, including small foci of tumor cells not evident in initial histologic sections.