PTGS2 and metastatic malignant neoplasm in the lymph nodes: Results: Immunohistochemical analysis performed on samples of primary melanomas revealed that 20/45 (44.4) cases were positive for PDL1 and 16/45 (35.5 %) for COX2; for lymph node metastasis 23/45 (51.1 %) cases were positive for PDL1 and 19/45 (42.2 %) cases for COX2.