CCDC6 (coiled-coil domain containing 6) is a tumor suppressor protein involved in critical cellular processes including DNA damage response and apoptosis 1. The protein functions as a structural component in the cytosol and participates in protein-protein interactions 1. CCDC6 acts as an ATM substrate responsive to genotoxic stress, sustaining DNA damage checkpoints and promoting apoptotic responses 2. When CCDC6 function is impaired through chr10 rearrangements or mutations, tumor progression is enhanced by impairing apoptotic responses, contributing to radio- and chemoresistance 2. CCDC6 forms oncogenic fusion genes with various proto-oncogenes (RET, and others) across multiple cancer types including thyroid and melanoma 3. Recent evidence indicates CCDC6 undergoes liquid-liquid phase separation and can regulate phase separation of fusion proteins 1. Additionally, CCDC6 collaborates with FBXO42 to control USP28-mediated p53 stabilization, influencing wild-type and mutant p53 levels in cancer 4. Beyond cancer, CCDC6 regulates cell fate decisions in liver and pancreatic tissues 5, and genetic variants near CCDC6 are associated with Alzheimer's disease risk 6. CCDC6 mutations may serve as predictive biomarkers for treatment resistance, potentially identifying patients who could benefit from PARP inhibitor therapy 2.