There is an upregulation of miR-181b in neuroblastoma, and this dysregulation is significantly associated with the prognosis of children with neuroblastoma.18 Another important finding is that miR-181b was up-regulated in MYCN-amplified neuroblastoma relative to the other tumor subtypes, while being decreased in retinoic acid-induced neuroblastoma.19 In contrast to earlier findings, however, some studies have shown that miR-181b has anti-cancer effects in other tumors. This evidence concerns the gene MYCN and cancer.