It's a frequently done test with many neuroblastomas because increased levels can indicate the presence of cancer or certain other diseases. Horners syndrome is sometimes associated with neuroblastoma. Oftentimes, when Horners syndrome occurs, it has been after some sort of neck surgery. This is a rare syndrome that can occur with neuroblastoma. Opsoclonus is characterized by spontaneous and chaotic movement of the eyes.
Myoclonus is involuntary and sudden movement of the trunk and extremities.
The MYCN gene, mapped to chromosome 2p24, is only one of many prognostic indicators for neuroblastoma.