JAG1 and breast cancer: Moreover, Jagged1, a canonical ligand of NOTCH receptors, was reported to modulate epithelial-to-mesenchymal transition in breast cancer cells through NOTCH signaling, increase the expression levels of SNAI2 and decrease those of CDH1. Jagged1 also modulates cell proliferation, as the inhibition of Jagged1 expression in MDA-MB-231 cells is sufficient to reduce cell cycle progression [5,47].