CDK9 and prostate carcinoma: CDK9 inhibitor II, CAN508 is an arylazopyrazole compound that inhibits CDK9 with 38-fold selectivity for CDK9/cyclin T over other CDK/cyclin complexes [14] and regulates CDK9 mediated c-MYC and androgen receptor transcription in breast and prostate cancers [15, 16].