To verify the relationship among hsa_circ_0072389, hsa_circ_0072386, hsa_circ_0008621, hsa_circ_0072387, and hsa_circ_0072391 with IKBIP, we knocked down hsa_circ_0072389, hsa_circ_0072386, hsa_circ_0008621, hsa_circ_0072387, and hsa_circ_0072391 in U251 glioma cells separately (Figure 4A–4E). The gene discussed is IKBIP; the disease is central nervous system cancer.