We investigated DDX1/MYCN gain by double-colour FISH on interphase nuclei.     ///    "Heterogeneous distribution of nuclei displaying DDX1/MYCN gain was observed in almost all tumours, suggesting a clonal evolution of cells with DDX1/MYCN gain. "    ///    "Moreover, all patients with DDX1/MYCN gain show a good overall survival but a high frequency of adverse events.. "