GPER1 and breast cancer: BPA (0.1 and 1 μM) was also shown to induce proliferative effects in both breast cancer cell lines (SKBR3 and MDA-MB-231 cells) and vascular endothelial cells under hypoxic conditions, which was associated with the GPER-mediated increase in hypoxia-inducible factor 1-α and vascular endothelial growth factor expression [125].