CDKN1A and cancer: Several drugs that target the cell cycle have also been evaluated in clinical trials with cancer patients.24This study found that fisetin triggered G1 phase arrest in LNCaP cells by activating WAF1/p21 and kip1/p27, followed by a reduction in cyclin D1, D2, and E as well as CDKs 2, 4, and 6.20In addition, screening study also examined the effects of flavonoids on the cell cycle of PCa cells.