MDM2 and neuroblastoma: It was recently shown that MYCN-directed centrosome amplification, leading to increased tumorigenesis, requires MDM2-mediated suppression of p53 activity in Neuroblastoma cells.59 Since p53 is located on chromosome 17p, it can be suggested that suppression of p53 is difficult when there are more than two copies of 17p, and thus there is no selective advantage in MYCN amplification in tumors carrying more than two copies of the full chromosome 17 (Neuroblastoma type 1).