PTGER4 and prostate cancer: The expression of S100P in the colon is mediated by prostaglandin E2 (PGE2)–prostaglandin E receptor 4 (PTGER4) signaling (Chandramouli et al., 2010), in prostate cancer by IL-6 (Hammacher et al., 2005), and in breast and cervical by glucocorticoids (Tothova et al., 2011).