KCNRG (potassium channel regulator) is a tumor suppressor gene located at chromosome 13.3 that functions as a negative regulator of potassium channel activity 1. The protein suppresses K+ channel activity, particularly targeting Kv1 family channels by retaining them in endomembranes and reducing their surface expression 12. KCNRG exhibits pro-apoptotic and antiproliferative effects in various cell lines, consistent with its role as a tumor suppressor 3. Mechanistically, KCNRG associates with the N-terminal T1 domain of potassium channels and functions as an ER-associated protein to regulate channel trafficking 2. The gene is clinically significant across multiple disease contexts: deletions and mutations are frequent in B-cell chr13 lymphocytic leukemia, multiple myeloma, and hepatocellular carcinoma, where haploinsufficiency contributes to tumor progression 34. Additionally, KCNRG serves as an autoantigen in autoimmune conditions, with anti-KCNRG antibodies strongly associated with pulmonary manifestations in autoimmune polyendocrine syndrome type 1 (APS-1) and thymoma-associated pneumonitis 567. The protein's expression is predominantly restricted to bronchial epithelial cells, making it a specific target in pulmonary autoimmunity 5.