Overall, we detected a low level of enrichment for the repressive mark H3K27me3 in the majority of the MYCN-amplified neuroblastoma samples, with the exception of the O-PDX sample (SJNBL046) which displayed a relatively high level of H3K27me3 (Supplementary Fig. S3A–S3D). The gene discussed is MYCN; the disease is neuroblastoma.