CDK1 and neoplasm: Silymarin significantly inhibits the proliferation of HGC-27 cells, reduces the expression levels of CDK1 and Cyclin B1, causes G2/M phase cycle arrest, and activates caspase 3 to cause Poly ADP-ribose polymerase cleavage as well as caspase 8 and caspase 9, ultimately leading to apoptosis of tumor cells (Cartee et al., 2001).