S1PR5 and carcinoma of esophagus: Furthermore, S1PR2 can block PDGF-induced proliferation of murine embryonic fibroblasts and rat hepatocytes (Goparaju et al., 2005, Ikeda et al., 2003) and S1PR5 inhibits proliferation of human oesophageal cancer cells whether it binds S1P or not (Hu et al., 2010).