Our results are in line with a publication of Gilabert-Oriol et al., who investigated the mode of action of SO1861 for endolysosomal escape of the toxin dianthin on a molecular level by fluorescence microscopy 36 and a publication of Thakur et al., where a 6,900-fold enhanced cytotoxicity of Sap3-EGF, consisting of EGF and the toxin saporin, was reached after addition of SO1861 in transfected breast cancer cells 40. Here, EGF is linked to breast cancer.