ACP3 and cancer: The binding of (S)‐A2855/B725 (16), the most potent ACP3 binder identified from the FM‐DEL platform, on tumor cells was further investigated on ACP3‐positive cancer cells (PC3.hACP3).[30] The compound bound to ACP3‐positive cells, as demonstrated by a fluorescence shift in flow cytometry experiments in comparison to cells incubated with a non‐targeted fluorescein control (C6‐FITC), non‐stained cells, and ACP3‐negative cancer cells [Figure 4E; Figure S44, Supporting Information].