CDK4 and colonic neoplasm: Several small-molecule inhibitors, such as botulin and periplocymarin, blocked cell-cycle progression in colon cancer cells by silencing PI3K/AKT signalling, accompanied by the expression of cycle-related proteins such as cyclin-dependent kinase (including CDK2, CDK4 and CDK6) and cyclins (Cyclin B1 or D1) [12,13,14].