ALK and neuroblastoma: This has been described for infantile hemispheric gliomas type I, which may fit into our DNA methylation analysis (Figure 3).3 Furthermore, as seen in common infant tumors that harbor ALK, inherent maturation as part of normal development is an alternative explanation of the morphological and clinical maturation of infantile high-grade gliomas into infantile low-grade gliomas.3 The phenomenon of spontaneous regression of solid tumors arising during embryonal development is known for pediatric tumors, known for pediatric tumors, most prevalent in neuroblastoma.5