Claudin-14 (CLDN14) is a member of the claudin family, transmembrane proteins critical for forming tight junctions that regulate paracellular permeability and maintain cell polarity. Encoded by the *CLDN14* gene, this protein is primarily associated with tissues like the kidney, inner ear, and liver. In the auditory system, CLDN14 is essential for maintaining the ionic composition of endolymph in the cochlea, with mutations linked to autosomal recessive deafness. In the kidney, it modulates calcium and magnesium reabsorption, and dysregulation has been implicated in hypercalciuria and kidney stone formation.
CLDN14 antibodies are tools used to study its expression, localization, and function. Monoclonal and polyclonal antibodies enable detection in immunohistochemistry, Western blotting, and flow cytometry, aiding research on its role in epithelial barrier integrity and disease mechanisms. In cancer, CLDN14 has dual roles: it may act as a tumor suppressor in hepatocellular carcinoma by inhibiting proliferation or as a promoter in breast cancer by enhancing metastasis. Antibodies targeting CLDN14 are explored for therapeutic potential, including blocking aberrant signaling in cancers or restoring tight junction function in renal or auditory disorders. However, clinical applications remain largely preclinical, requiring further validation of specificity and safety. Research also investigates CLDN14 as a biomarker for diseases like chronic kidney disease or hearing loss. Challenges include understanding tissue-specific interactions and resolving conflicting data on its pro- or anti-tumor effects across cancer types.