Expression of pan-neuroendocrine proteins in 53 neuroblastic tumors. An immunohistochemical study with neuron-specific enolase, chromogranin, and synaptophysin.

The presence and distribution of pan-neuroendocrine markers such as neuron-specific enolase (NSE), chromogranin (CG), and synaptophysin (SYP) were investigated by immunohistochemistry in 53 cases of neuroblastic tumors, including three cases of ganglioneuromas, 17 ganglioneuroblastomas, and 33 neuroblastomas. In ganglioneuromas, all three markers were observed both in ganglion cells and in neurofibrils. All cases of ganglioneuroblastoma were positive for these markers, however, some variability of staining intensity was noted. Of the 33 cases of neuroblastomas, all were positive for NSE, 23 (70%) for CG, and 31 (94%) for SYP. Neuron-specific enolase was detected not only in the majority of the neuroblasts showing signs of differentiation, but also in some undifferentiated neuroblasts. Chromogranin was found mainly in differentiated neuroblasts with enlarged cytoplasm and nuclei, but was scarcely found in undifferentiated cells. Synaptophysin was detected in some undifferentiated neuroblasts, as well as in differentiated neuroblasts. Two cases without SYP-positive cells were also negative for CG. Our observations conclude that antibodies against NSE and SYP are helpful as a diagnostic aid for neuroblastic tumors.