Medulloblastoma is a cerebellar tumor affecting children and young adults, and 
accounts for approximately one fifth of all pediatric brain tumors. Despite 
multimodal therapy that includes surgery, radiotherapy and chemotherapy, 
recurrence is frequent and overall mortality rate remains relatively high. 
Moreover, radiation therapy results in severe effects on intellect, and younger 
age of treatment correlates with larger deficits. Improvements in therapy of 
this childhood tumor will focus increasingly on the clarification of the exact 
cellular origin and the genetic mechanisms contributing to tumor formation, and 
on new targeted therapeutic options. Aberrant activation of the Hedgehog (Hh) 
and Wnt developmental pathways is associated with medulloblastoma, but 
deregulation of other molecular pathways, including insulin-like growth factor 
(IGF) signaling, has also been implicated in the pathogenesis of the tumor. 
Recent observations in mouse models have demonstrated the importance of genome 
surveillance, as defects in DNA repair pathways in animals can lead to genomic 
instability in neural progenitor cells, resulting in medulloblastoma. The 
current review will focus on the most recent findings on the molecular pathology 
of medulloblastoma and discuss their potential contribution to treatments 
directed by the molecular alterations.