GGNBP2 (gametogenetin binding protein 2) is a multifunctional protein with roles in immune regulation, tumor suppression, and potentially spermatogenesis. Mechanistically, GGNBP2 regulates MDA5-mediated innate immune sensing by modifying subcellular distribution of double-stranded RNA substrates and reducing cytoplasmic dsRNA accumulation following ADAR1 loss 1. GGNBP2 also functions as a structural platform for protein-protein interactions within the CNOT1-CNOT10-CNOT11 complex, binding to the CNOT11 antenna domain 2. As a tumor suppressor, GGNBP2 suppresses proliferation, invasion, and migration across multiple cancer types—glioma, prostate cancer, and triple-negative breast cancer—primarily through inhibition of PI3K/Akt and Wnt/β-catenin signaling pathways, with IL-6/STAT3 pathway suppression in breast cancer 345. Notably, a circular RNA-derived protein (cGGNBP2-184aa) acts oppositely, promoting IL-6/STAT3 signaling in cholangiocarcinoma 6. Genetically, GGNBP2 shows pleiotropy with shared risk loci identified in obesity-multiple sclerosis comorbidity and amyotrophic lateral sclerosis-autoimmune disease associations 78. Downregulation correlates with poor prognosis in multiple cancers.