KCTD11 is a tumor suppressor protein that functions as a negative regulator of oncogenic signaling pathways, particularly the Hedgehog pathway in medulloblastoma. Mapped to chromosome 17.2, KCTD11 inhibits medulloblastoma cell proliferation and colony formation in vitro and suppresses xenograft tumor growth in vivo by antagonizing GLI1-mediated transactivation of Hedgehog target genes through effects on GLI1 nuclear transfer 1. At the molecular level, KCTD11 acts as a substrate-specific adapter for the Cullin3-RING ubiquitin ligase complex (CRL3REN), promoting polyubiquitylation and degradation of oncogenic proteins like SALL4 2. Additionally, KCTD11 activates the Hippo pathway in hepatocellular carcinoma, enhancing p21 expression and suppressing cell migration, invasion, and epithelial-mesenchymal transition 3. Loss of KCTD11 expression is a common event across multiple cancer types, including medulloblastoma, prostate adenocarcinoma, and hepatocellular carcinoma, correlating with worse overall survival 1, 4, 3. KCTD11 expression is regulated by Sp1 transcription factor and DNA methylation, and its down-regulation through loss of heterozygosity and hypermethylation represents a significant tumorigenic mechanism 5. Beyond cancer, KCTD11 shares functional conservation with yeast Whi2 in nutrient sensing through mTORC1 suppression under low amino acid conditions 6.