PTGS2 and metastatic malignant neoplasm in the lymph nodes: In addition, COX-2 expression was significantly related to the diameter of tumor (p = 0.003), invasion depth (p < 0.001), lymph node metastasis (p < 0.001), distant metastases (p = 0.017), poor tissue differentiation (p = 0.015), and advanced TNM staging (p < 0.001), but not the gender of patients (p = 0.971) (Table 2).