PTGS2 and neoplasm: As COX-2 and its downstream products such as PGE2 have widespread immune-modulatory roles in the development of tumor-associated suppressive macrophages and MDSCs30, 31, we then investigated the PGE2 level after doxorubicin treatment and observed a significant enhanced production of PGE2 in 4T1 cells with chronic exposure to 50 nM doxorubicin in a time dependent manner (Fig. 2D).