Finally, addition of CXB during pre-treatment of COX-2WT 4T1 cells with 5-FU reduced the levels of IL-6 and IL-1α detected in the peritoneum (Fig. 5g, h), further exposing the major contribution of COX-2 enzymatic activity for the inflammatory properties of CTX-treated cancer cells in vivo. This evidence concerns the gene IL6 and cancer.