Amplification of N-myc oncogene in stage II and IVS neuroblastomas may be a prognostic indicator.

The amplification of N-myc oncogene is frequently observed in tumors of patients with advanced, poor prognostic stages of neuroblastoma (unfavorable stage group). However, there has been little documentation of the N-myc amplification in tumors of patients with stages II and IVS neuroblastoma (favorable stage group). In this communication, we present data on one patient in stage II and two in stage IVS. In these children, the primary tumors had an amplified N-myc and the clinical course was poor. In addition, from an analysis of the N-myc oncogene of 26 neuroblastomas, genomic amplification of more than three copies was observed in 4 of 11 (36%) in the favorable stage group, and in 9 of 15 (60%) in the unfavorable stage group. Death occurred only in those with an amplified N-myc, in both groups. The smaller copy number of N-myc amplification of stage IVS tumors as compared with those of stages III and IV, appeared to be characteristic. These findings suggest that N-myc amplification may be a reliable prognostic indicator even in the favorable stage group of neuroblastomas, and may be clinically useful as a guide for treating those with a poor prognosis in stages II and IVS.