PTGS2 and breast cancer: Cyclooxygenase-2 (COX-2) (Miller et al. 2005; Ristimaki et al. 2002; Singh et al. 2007), tumor necrosis factor-alpha (TNF-α) (Danforth and Sgagias 1996), vascular endothelial growth factor (VEGF) (Byrne et al. 2007) and IL-6 (Lin et al. 2015) are all inflammation mediators that play critical roles in metastasis and progression of breast cancer.