MYCN and neuroblastoma: Eight tumors displayed gain of the entire chromosome 3 (Figure 4a and Supplementary Figure 4b), which is partially syntenic to human chromosome 1q, a region often gained in human neuroblastomas.10 Interestingly, two tumors showed a focal gain on chromosome 6 that encompassed the ROSA26 locus, in which the human MYCN transgene was integrated (Figures 4a and b).