Because of the slight increase in CDK9 inhibitory activity and degradation of CDK9, B03 exhibited significantly better anti-proliferative activity against MV4–11 than BAY1143572, indicating that its degradation activity is superior to its inhibitory effect.109 B03 exerts anti-proliferative activity against cancer cell lines (MV4–11, MOLM13, HCT-116, B16, A549, HepG2, and MCF7).109. This evidence concerns the gene CDK9 and cancer.