Tumors of the neuroblastoma group.

The basic histologic changes associated with the maturational sequences of neuroblastoma tumors are reviewed. The author describes a histopathologic classification system developed for distinguishing favorable and unfavorable prognoses, based on the combination of tumor morphology and patient's age at diagnosis. Also discussed are the results of recent analyses of the biologically significant relationship between histologic findings and molecular markers, such as amplification of the N-myc oncogene and expression of the nerve growth factor receptor gene. Clinical trials involving neuroblastoma tumors are briefly reviewed.