CDKN1A and central nervous system cancer: In the G/S phase, REV‐ERBα inhibits p21 to promote cell progression,52 RORα activates p21 to inhibit cell progression,53 DEC1 inhibits cyclin D1,54 and CLOCK/BMAL1 negatively regulates c‐Myc55; in the G/M phase, BMAL1/CLOCK, BMAL1/NPAS2 or CRY1 acts on Wee1 to inhibit or activate glioma process56 (Figure 1).