PTGER4 and B-cell non-Hodgkin lymphoma: Furthermore, also consistent with the earlier findings on PGE2‐mediated inhibition of B cells activation (Roper et al., 1994), Murin et al. found that PGE2 suppresses B cell receptor‐mediated proliferation of B cells lymphomas through EP4 receptors and that gene knockdown of Ptger4 (encoding EP4 receptor) in B cells lymphoma markedly accelerates tumour spread in mice, while PTGER4 overexpression yields significant protection (Murn et al., 2008).