several genes including microRNA miR-34a, [ 27 ] WAF1/CIP1 encoding for p21 and hundreds of other down-stream genes. p21 (WAF1) binds to the G1 - S / CDK ( CDK2 ) and S/CDK complexes (molecules important for the G1/S transition in the cell cycle) inhibiting their activity. When p21(WAF1) is complexed