Using two neuroblastoma cell lines, SH-SY5Y characterized by very low levels of NEP expression, and NB7 which produce a significant amount of NEP we have demonstrated that in the case of low NEP-expressing cells the NEP promoter is occupied by the histone-deacetylase HDAC1 while in NB7 cells by AICD. The gene discussed is MME; the disease is neuroblastoma.