FAP and melanoma: In accordance, only the HER2’scFv bearing liposomes (HER2-IL, Bi-FAP/HER2-IL) were taken up and activated by the HER2 expressing cells (Figure 4A,B) whereas the FAP-based formulations (FAP-IL, Bi-FAP/HER2-IL) were firmly taken up and activated by the HT1080-hFAP cells or mildly by the low FAP-expressing melanoma cell line, causing an intense red (DY676-COOH) and green (NBD-DOPE) fluorescence of the cells (Figure 4C,D).