Increased COX-2 activity resulted in resistance to tamoxifen.52 Elevated COX-2 activity was not associated with reduced doxorubicin or taxane sensitivity.52 The aforementioned observations point to the important role of the COX-2 signalling pathway and the eicosanoid system in hormone-dependent and-independent breast cancer cells. Here, PTGS2 is linked to breast carcinoma.