Cianciaruso et al. inoculated colon adenocarcinoma (MC38) and murine breast cancer cells (E0771) subcutaneously in C57BL/6 mice, and they found that TAM-EVs isolated from tumor-bearing mice contained bioactive lipids and biosynthetic enzymes of the arachidonic acid pathway such as COX1, thromboxane-A synthase (TBXAS1), and some CYP proteins, which redirect the catabolism from a COX2-dependent pathway toward a COX1-dependent pathway to limit the pro-tumoral effects of some prostaglandins. Here, PTGS2 is linked to breast carcinoma.