CLDN7 and esophageal squamous cell carcinoma: In esophageal squamous cell carcinoma cells, CLDN7 is often absent or localized to the cytoplasm, rather than confined to the cell membrane as in normal esophageal cells (32) In addition, the dysregulation of CLDN7 may lead to decreased E-cadherin expression, loss of epithelial architecture and an increase in the invasion observed in squamous cell carcinoma.