CLDN11 and cancer: Recent studies have shown that the downregulation of CLDN11/OSP contributes to the malignancy of various cancers, as indicated by an increased degree of invasiveness, metastasis promotion, and poor prognoses in colon cancer [15], gastric cancer [16], and laryngeal squamous cell carcinoma [17] while the forced expression of CLDN11/OSP in bladder cancer decreases the degree of invasiveness [18].