SHH and medulloblastoma: In addition, trials such as SJMB12 also investigated intensified treatment regimens for patients in higher-risk subgroups, including the addition of gemcitabine and pemetrexed for those with high-risk Group 3 or Group 4 medulloblastoma, and targeted SHH inhibitor therapy for those with SHH-positive medulloblastoma [27].