Of note, five (62.5%) of the eight patients ceased crizotinib without experiencing relapse or PD, which indicates that it is possible to cease crizotinib in AP-IMT without rapid disease recurrence as has been reported in ALCL.44 The toxicity profile observed was in line with the COG clinical trial.28,29 The most notable ongoing toxicity during crizotinib treatment was moderate to severe neutropenia, which was managed by intermittent granulocyte colony-stimulating factor. The gene discussed is CSF3; the disease is neutropenia.