To do this, breast cancer cells expressing mCherry (red fluorescentprotein) were injected into DoC of fli1/Casper fishat 2 dpf, as previously established.79 Thexenograft cells homogeneously disseminated through the circulatorysystem to the tail of the zebrafish, where they attached to endothelialcells of the vessels and formed multiple tumor foci.77,79 One hour postinjection (hpi) of the tumor cells, far-red fluorescentDiD-labeled LNPs were injected through the dorsal aorta into zebrafish(Figure S4a). This evidence concerns the gene FLI1 and breast cancer.