An international prospective trial on medulloblastoma (MB) in children older than 3 to 5 years with WNT biological profile (PNET5 MB – LR and PNET5 MB – WNT-HR), average-risk biological profile (PNET 5 MB – SR), or TP53 mutation (PNET 5 MB – SHH-TP53), and Registry for MB occurring in the context of genetic predisposition (PNET 5 – Registry)