ESYT1 and breast cancer: As E-Syt1 and E-Syt2 are required for full activation of SOCE in a variety of breast cancer cells, including ER+ breast cancer MCF7 cells and the TNBC cell lines MDA-MB-231 and BT20, we have explored their roles in cell viability by using the cell-permeant dye calcein and propidium iodide (PI).