BSJ-5-63 is a potent CDK12, CDK7, CDK9 PROTAC degrader. BSJ-5-63 BSJ-5-63 decreases the protein expression of CDK12, CDK7, CDK9, RNAPII, Cyclin K. BSJ-5-63 decreases the mRNA expression of BRCA1, BRCA2. BSJ-5-63 shows anticancer activity and has the potential for the research of prostate cancer (Pink: ligand for target protein ; black: linker (HY-W140827) ; Blue: E3 ligase ligand (HY-112078) ).