This may be due to several factors and limitations, including a limited impact of rTMS on the BBB, potentially not allowing sufficient levels of IGF-Trap to reach the brain and intra-tumor heterogeneity of glioblastoma cells—a characteristic of these tumors [2] with pre-existing subpopulations within the tumors that were not sensitive to IGF-signaling inhibition. The gene discussed is IGF1; the disease is glioblastoma.