Synaptophysin--an immuno-histochemical marker for childhood neuroblastoma.

Synaptophysin, an integral membrane glycoprotein of presynaptic vesicles, was tested as an immuno-histochemical marker for childhood neuroblastoma. Synaptophysin immuno-reactivity was found in all neuroblastomas (6/6), but not in the other small round-cell tumors to be considered in its differential diagnosis. Thus, rhabdomyosarcomas (0/5), lymphomas (0/4), or Ewing's sarcomas (0/2) were negative for synaptophysin. The results suggest that synaptophysin is a useful marker for neuroblastoma, and it should belong to the marker panel used for the differential diagnosis of small round-cell tumors of childhood.