Outline: This is a multicenter study. Patients are stratified according to molecular subgroup assignment (WNT, SHH, or Non-WNT Non- SHH) and then by clinical risk stratification (extent of resection, M stage, histologic subtype, and cytogenetic features). All patients will be treated with risk-adapted radiation therapy and adjuvant chemotherapy. Patients assigned to Stratum W1 will receive reduced dose radiation therapy. Patients assigned to Stratum W2, S1, N1, or N2 will receive standard dose radiation therapy. Patients assigned to Stratum W3, S2, or N3 will receive high dose radiation therapy. Radiation therapy will be followed by 4 cycles of adjuvant conventional chemotherapy with cyclophosphamide, cisplatin and vincristine for all patients. Patients assigned to Stratum N2 or N3 (Non-WNT Non-SHH with high risk factors) will receive 3 additional cycles of pemetrexed and gemcitabine chemotherapy intermixed into the conventional adjuvant chemotherapy cycles. Patients with SHH subtype (Stratum S1 or S2) who are skeletally mature will receive 12 months additional maintenance therapy with vismodegib.