Xie et al. [139] reported that APC/C–Cdc20, which is transcriptionally controlled by Forkhead transcription factor M1 (FoxM1), maintains tumor initiating cells (TICs) through degradation of p21CIP1/WAF1, a critical negative regulator of TICs in glioblastoma. This evidence concerns the gene CDKN1A and glioblastoma.