In contrast to GBM, where repetitive injections of the targeting vector are required to achieve temporary tumor control, a single intra-tumoral injection of [213Bi]Bi/[225Ac]Ac-DOTA-substance P was found to be sufficient to achieve long-lasting tumor control in both grade 2 oligodendrogliomas (n = 1) and diffuse grade 2 infiltrative astrocytomas (n = 8). This evidence concerns the gene TAC1 and glioblastoma.