Xu et al. showed in PC-3 prostate cancer cells that EP4 antagonism (or EP4 siRNA) attenuates the PGE2-mediated expression of matrix metalloproteinases, nuclear factor-κB ligand, and runt-related transcription factor 2, which promote cell growth and metastasis in multiple cancers [47]. Here, PTGER4 is linked to prostate carcinoma.