P2RY2 and breast cancer: Moreover, adhesion of MDA-MB-231 to ECs that were stimulated with ATP or UTP (10 μM) increased approximately 3-fold compared to non-treated cells, whereas transfection of P2Y2R siRNA in ECs and MDA-MB-231 markedly reduced the effect of ATP or UTP on breast cancer cell-EC adhesion (Figure 3E).