High Incidence of MYCN Amplification in a Moroccan Series of Neuroblastic Tumors: Comparison to Current Biological Data

MYCN protooncogene status was assessed for the first time in Morocco in peripheral neuroblastic tumors, including neuroblastoma, ganglioneuroblastoma, and ganglioneuroma. Correlations with age at diagnosis, stage, mitosis-karyorrhexis index, differentiation, and Shimada histology were evaluated. Thirty-six formalin-fixed, paraffin-embedded peripheral neuroblastic tumor tissue specimens collected between 2007 and 2010 from the Pathology Department were assessed for MYCN amplification using fluorescence in situ hybridization. MYCN amplification was found in 27.8% of cases. An association of MYCN amplification with unfavorable Shimada grading, higher mitosis-karyorrhexis index, and undifferentiated morphologic phenotype was found. We found no correlation with older age, advanced stage, or the presence of metastasis. Our results suggested that the presence of MYCN amplification is a strong biological indicator of a poor outcome and aggressive disease in neuroblastoma and nodular ganglioneuroblastoma.