OCLN and breast cancer: In vivo studies have also shown associations between reduced occludin expression and distant metastasis in breast cancer [13,14], high tumor grade in colon cancer [15,16], lymph node metastasis in endometrial cancer [17], lymph node and peritoneal metastasis in gastric cancer [18], and poor prognosis in esophageal [19] and gall bladder cancer [20].