Cornulin (CRNN)

Cornulin (CRNN) is a calcium-binding protein predominantly expressed in stratified squamous epithelial tissues such as the skin, esophagus, and cervix[2][4][5]. It belongs to the S100-fused type protein family and is characterized by EF-hand Ca2+ binding domains and repeat-rich C-terminal regions[3][4]. Cornulin is involved in epithelial differentiation and functions as a stress-response protein, potentially acting as a tumor suppressor in squamous cell carcinomas, where its expression is often downregulated during progression[2][5]. However, overexpression of Cornulin in some cancers has cancer-promoting effects by facilitating cell cycle progression and inhibiting apoptosis[1]. It has been shown to regulate epidermal growth, cell cycle G1/S transition (via cyclin D1), and responds to inflammatory or stress signals, with its level serving as a useful biomarker for cancer diagnosis and prognosis in squamous epithelium-derived malignancies[1][2][5]. There are no approved therapeutic drugs that directly target cornulin, and it is not currently considered a direct druggable or therapeutic target.

Other names

CornulinCRNNC1orf10DRC1PDRC1SEP5353 kDa putative calcium-binding protein53 kDa squamous epithelial-induced stress protein58 kDa heat shock proteinsquamous epithelial heat shock protein 53tumor-related protein