Conversely, MYCN KD was found to downregulate MDM2 in IMR-32 neuroblastoma cells (20) but not in NB-1691 and NB-1643 neuroblastoma or RB176 retinoblastoma cells (16, 17), implying that MYCN dependent MDM2 expression is cell line-specific. Here, MDM2 is linked to retinoblastoma.