In addition, Lin et al. demonstrated in pre-clinical models that treatment with EP4 antagonist GW627368X reduces tumor chemoresistance of breast cancer and colorectal tumors in vivo when used in combination with paclitaxel, thus demonstrating that EP4 antagonists could be a viable addition to chemotherapeutic treatment for a variety of cancers including LMS [56]. Here, PTGER4 is linked to breast carcinoma.