CDK4 and prostate carcinoma: It was found that EGCG could irreversibly induce cell cycle G1 phase arrest, ultimately leading to apoptotic cell death by upregulation of WAF1/p21, KIP1/p27, INK4a/p16, and INK4c/p18, and downregulation of cyclin D1, cyclin E, cdk2, cdk4, and cdk6, irrespective of p53 status, in prostate carcinoma cells[29].