SHH and medulloblastoma: According to the molecular characteristics of the fifth edition of the WHO Classification of Tumors of the Central Nervous System (CNS), published in 2021, medulloblastomas are defined into four groups: WNT-activated, SHH-activated and TP53-wildtype,SHH-activated and TP53-mutant and non-WNT/non-SHH [5].