Following treatment of NB cells with 5 μm or 10 μm DZNep, SAHA and 5‐Aza, DZNep and SAHA were shown to exert a synergistic effect while 5‐Aza specifically suppressed the expression of DNMT1, but not EZH2 or HDAC1. This evidence concerns the gene HDAC1 and neuroblastoma.