DPP4 and neoplasm: Moreover, the applicability of this new probeas an intracellular in vivo sensor of DPP IV activity,as well as its ability to obtain clear fluorescence microscopy imagesof tumor tissues when excited by two photons, has been confirmed.In addition, the fluorophore released by enzymatic action has beenfound to be suitable for superresolution fluorescence microscopy imaging.Finally, zebrafish embryos and larvae at 1, 3, 5, and 7 dpf were incubatedwith the probe.