MYCN and neuroblastoma: However, ONC201 not only downregulated ATRX expression in non-MYCN-amplified NB cells in vitro, but also found that ONC201 did not achieve upregulate ATRX in non-MYCN-amplified xenografts, whereas it contributed to significant upregulation of ATRX in MYCN-amplified SK-N-DZ xenografts [5]; this upregulation may have been related to a decrease in MYCN protein expression.