CCNK encodes cyclin K, a regulatory subunit of cyclin-dependent kinases (CDKs) that plays a critical role in transcriptional regulation and DNA damage response. CCNK primarily functions by forming complexes with CDK12 and CDK13, which phosphorylate the C-terminal domain of RNA polymerase II to regulate transcription elongation 12. The protein is essential for neural development, as CCNK deficiency causes intellectual disability syndrome characterized by deficient neural progenitor cell (NPC) proliferation and enhanced apoptotic cell death through dysregulated WNT5A signaling 3. CCNK demonstrates clinical relevance as a therapeutic target in cancer, where its degradation compromises CDK12 function, reduces DNA damage response gene expression, and induces cell death 24. In prostate cancer, CCNK downregulation promotes androgen receptor variant expression and creates vulnerability to PARP inhibitor treatment 5. Multiple molecular glue degraders have been developed that selectively target CCNK for ubiquitination and proteasomal degradation by promoting interactions between CDK12-CCNK complexes and CUL4-DDB1 E3 ubiquitin ligases 126. These compounds show broad-spectrum antitumor activity and represent a promising therapeutic approach for cancer treatment.