The expression of claudin-5 was not associated with age (P = 0.364), histological grade (P = 1.000), or expression of Ki67 (P = 1.000), whereas it was associated with lymph node metastasis (P < 0.05) and clinical staging (P < 0.01). This evidence concerns the gene CLDN5 and metastatic malignant neoplasm in the lymph nodes.