PHOX2B and neoplasm: So far, mutations of only two genes have been identified as disease-causing in hereditary NBL: the paired-like homeobox 2B gene (PHOX2B), a key enzyme in early sympathic neurogenesis [18] and a tumor suppressor in NBL metastasis, and the anaplastic lymphoma kinase (ALK) gene, playing a role in both familial and sporadic NBLs [5, 19, 20].