MUC1 and cancer: By further incorporating therapeutic agents, doxorubicin (Dox) and the tumor‐targeting MUC1 aptamer (Apt), these multifunctionalized Dox‐SDH‐Apt systems can specifically target cancer cells and selectively release the preloaded therapeutic agents via structure switching when in an ATP‐rich intracellular environment, leading to the activation of the fluorescence and efficient treatment of cancer cells[204] (Figure 9B).