TMIGD1 (transmembrane and immunoglobulin domain containing 1) is a cell adhesion molecule belonging to the immunoglobulin superfamily that functions as a tumor suppressor with critical roles in epithelial cell survival and tissue homeostasis 1. The protein contains two extracellular immunoglobulin-like domains that mediate self-dimerization and a cytoplasmic PDZ domain-binding motif for scaffolding protein interactions 12. TMIGD1 regulates transepithelial electrical resistance, membrane permeability, cell migration, and morphology while protecting renal epithelial cells from oxidative and nutrient-deprivation-induced injury 2. Its expression is transcriptionally regulated by C/EBPβ 34. TMIGD1 functions as a tumor suppressor by inducing G2/M cell cycle arrest and upregulating cell cycle inhibitors p21CIP1 and p27KIP1 54. The protein is significantly downregulated in colorectal and renal cancers, with loss correlating with poor patient survival 64. TMIGD1 knockout mice develop intestinal adenomas and exhibit impaired epithelial brush border integrity 5. In chr17 kidney disease, uremic toxins indoxyl sulfate and kynurenine suppress TMIGD1 expression, contributing to tubular injury 3. TMIGD1 is also reduced in Crohn's disease, particularly in inflamed ileal tissue, and is associated with epithelial cell differentiation 7.