NTRK1 and neuroblastoma: Other notable genetic changes in neuroblastoma include overexpression of ornithine decarboxylase 1 (ODC1), the rate-limiting enzyme in polyamine biosynthesis, activating mutations in the receptor tyrosine kinase (RTK) anaplastic lymphoma kinase (ALK), and loss-of-function mutations in the homeobox gene PHOX2B that are present in children that develop sporadic or familial neuroblastoma [[21], [22], [23]].