The anthracycline doxorubicin is a well-characterized DNA-intercalating drug that is used in the therapy of neuroblastoma, combined with cisplatin, etoposide and cyclophosphamide (CEDC regime).45 Modulation of histone acetylation levels by HDAC inhibitors led to increased cytotoxicity of doxorubicin in vitro. Here, HDAC9 is linked to neuroblastoma.