PTGS2 and breast cancer: A total of 17 studies demonstrated an important relationship between the phenotype of COX-2 and one or more of the histopathologic parameters of BC cases such as age, tumor size, histological type, tumor grade, advanced stage, lymph nodes metastasis, lymphovascular invasion, distant metastasis, surgical margins, and disease recurrence or shorter DFS.17-21,23-27 On the other hand, 3 studies found an inverse association with grade and DFS, and few other reports could not find such relationships.22,28,30-33