KCTD12 (potassium channel tetramerization domain containing 12) is a multifunctional protein with distinct roles in cellular signaling and cancer biology. As an auxiliary subunit of GABA-B receptors, KCTD12 modulates receptor pharmacology and kinetics, and has been identified as a component of the μ-opioid receptor proximal proteome, where it may function as part of a G-protein buffering system 1. In cancer contexts, KCTD12 exhibits contradictory functions depending on cancer type. In colorectal cancer, KCTD12 acts as a tumor suppressor by inhibiting cancer stem cell properties through suppression of the ERK pathway and stemness markers like CD44, CD133, and CD29 2. Conversely, in other cancers, KCTD12 promotes tumorigenesis by facilitating G2/M cell cycle transition through interaction with CDC25B/CDK1/Aurora A pathway, with Aurora A creating a positive feedback loop by phosphorylating KCTD12 at serine 243 3. KCTD12 also regulates ferroptosis in colon cancer through the SLC7A11 axis 4. Clinically, KCTD12 expression levels correlate with patient outcomes in multiple cancer types and may serve as a diagnostic biomarker for EGFR-TKI resistance in lung adenocarcinoma 5. Additionally, KCTD12 has been associated with rumination behavior through genome-wide association studies 6.