S1PR4 and breast carcinoma: A previous study [60] indicated that JTE013 was both an S1PR2 and S1PR4 antagonist because JTE013 (10 μM) was reported to inhibit S1P-induced p-ERK expression in MAD-MB-453 breast cancer cells, and a S1PR4 siRNA also reduced the S1P-induced p-ERK, while a S1PR2 siRNA failed to reduce the S1P-induced p-ERK expression in MDA-MB-453 breast cancer cells [60].