TP53 and medulloblastoma: For example, most WNT-activated medulloblastomas are of classic histology (as are most non-WNT/non-SHH medulloblastomas), most SHH-activated cases with TP53-mutation show an anaplastic phenotype, and almost all desmoplastic/nodular medulloblastomas and those with extensive nodularity are SHH-activated [20].