Moreover, tCDK inhibitors such as SY-5609 (CDK7)29, THZ1 (CDK7, CDK12/13)30,31, THZ2 (CDK7, potentially CDK12/13)32,33, AZD4573 (CDK9)34, THZ531 (CDK12/13)35–37 and cortistatin A (CDK8/19)17,38 among several others have demonstrated significant anti-tumor activity in preclinical studies. This evidence concerns the gene CDK9 and neoplasm.