On a different note, data here reported on the cross-talks between Notch and ER in endothelial cells suggest that it would be of interest to determine the possible effects on angiogenesis of currently used drugs for cancer therapy (aromatase inhibitors and/or ER antagonists) or under clinical investigation (γ-secretase complex inhibitors [59]–[62]), which are targeting either one of these pathways. This evidence concerns the gene ESR1 and cancer.