CLDN7: Epithelial gatekeeper from physiology to pathology‑roles in cancer and epithelial‑related diseases (Review)

Claudin‑7 (CLDN7) is a key component of epithelial tight junctions. It plays a vital role in maintaining cell polarity, barrier integrity and paracellular transport. Abnormal CLDN7 expression is closely related to the onset and progression of various diseases. It is especially markedly associated with the growth and metastasis of multiple cancers. Additionally, dysregulated CLDN7 expression contributes to the progression of intestinal, skin and respiratory system diseases. The present review summarized the structure, expression, physiological functions, stability and regulatory mechanisms of CLDN7, emphasizing its role in tumors. The expression patterns, regulatory mechanisms, effect on malignant phenotypes and clinical significance of CLDN7 were also discussed.