EDNRA and cancer: According to the role of ET-1 as a mitogenic factor for cancer and stromal cells [22, 23, 28, 31], cell proliferation and live–dead assays show that ET-1 increases cell vitality, while the addition of AMB, or BQ788 or BOS, as well as silencing of β-arr1 in both cell types, significantly block the basal or ET-1 effects (Supplementary Fig. 6D, E), confirming the presence of an ET-1/ETA/BR autocrine loop and the involvement of β-arr1 in cancer-associated ovarian stromal cells.