CDK4 and neuroblastoma: The involvement of cell cycle regulators such as PLK1 [4], TRIM16 [5], WEE1 [6], CDK4/6 [7], and CCND1 [8] in various aspects of neuroblastoma pathogenesis suggests that deregulation of the normal cell cycle could be an important factor in driving neuroblastoma tumorigenesis and opens the possibility that more oncogenic cell cycle regulators could be identified by screening a large set of cell cycle regulators.