EPCAM and neoplasm: The tumor signal intensity of targeted NPs was much stronger than that of non-targeted NPs at tumor tissue during the experimental period (both 12 and 24 h) (Figures 9A, B), further confirming that Apt-PEG-Au-NPs@5-FU can target HT-29 tumors, probably by both passive (EPR effect-mediated) and active (EpCAM aptamer) mechanisms.