CDK4 and cancer: These anti‐cancer activities of PBSA in ovarian cancer cell invasion and proliferation were mediated by the inhibition of mitogen‐activated protein kinase kinase 3/6‐p38 mitogen‐activated protein kinase (MKK3/6‐p38MAPK) activity and subsequent down‐regulation of MMP‐2, MMP‐9, Cdk4, Cdk2 and integrin β1, as evidenced by treatment with p38MAPK inhibitor SB203580.