SHH and medulloblastoma: The importance of Shh to cerebellar histogenesis is underscored by elegant genetic analyses demonstrating that levels of SHH signaling control the foliation patterning of the cerebellar cortex [64] (see “Cerebellar Foliation” section), and studies on human medulloblastoma (MB) implicate defects in SHH signaling in MB formation (reviewed in [65], see “Deregulated Developmental Pathways in Medulloblastoma” section).