Comparison of the expression of claudin-7 at the invasive front of the esophageal cancer with that in the corresponding metastastic lymph nodes showed significantly reduced claudin-7 expression in metastastic lymph nodes, indicating that claudin-7 may be a predictor of lymph node metastasis [50]. This evidence concerns the gene CLDN7 and metastatic malignant neoplasm in the lymph nodes.