The success rate of GBM on CAM engraftment was 98.3% [110], 38–69% in heterotopic mouse models of patient-derived xenograft gliomas [109,111], and 76–90% in an orthotopic mouse model of a brain tumor [109,112]; however, the problem is that IDH1-mutated transplanted specimens almost entirely fail in mice [111,113,114], and in contrast, patient-derived xenografts on the CAM are practically always successful [110]. Here, IDH1 is linked to glioma.