CDK2 and plasma cell myeloma: Several key signaling factors, which are responsible to growth/apoptosis regulation, including cyclin A or B, CDK2, cyclin E and caspase 3, were also reduced or activated by icaritin treatment, suggesting although icaritin may potently inhibits the JAK2/STAT3 signaling axis in U266 cells, the crosstalk or inhibition of other signal pathways, such as cell cycle-regulated or apoptosis signalings, obviously was involved in the mechanisms of icaritin for anti-myeloma activity.