In our present study, therefore, we designed an array of peptides that span the AGO2-interacting region of C-terminal MSI1, aiming to identify smaller companions at around 15 amino acids long that could function as decoys to interfere with protein–protein interaction between MSI1 and AGO2, and to disrupt subsequent oncogenic events in cancer cells thereby conferring therapeutic efficacies for patients with malignant brain tumors and glioblastoma (GBM) (Figure 1B). The gene discussed is AGO2; the disease is brain cancer.