PTGER4 and cancer: Receptors for eicosanoids in PRN and PRT cancer models (Fig. S5A, B) are primarily located in immune cells and fibroblasts: Fpr2 is located in granulocytes, Cysltr1 and Ptger4 in macrophages (and B cells in PRT), Ptger3 in fibroblasts, while Ptgir is found in smooth muscle cells.