PER1 and neuroblastoma: Validations in neuroblastoma culture could largely reproduce crucial insights and the prominent alterations found in the cerebellar transcriptome: Strong reduction of Atm levels was reflected in similar strong decreases of its interactor Usp2, the mainly Purkinje-neuron-expressed Ca2+-excitability modulator Itpr1 mRNAs, and immediate-early signalling factors such as Per1 and Nr4a1.