In another report involving a dual-mode peptide design strategy,Zheng and co-workers developed a small library of HDAC-responsivetheranostic agents 47a–c based onCPT decorated with various peptide sequences for multistage tumortargeting purposes.249 The peptides usedby the authors were 1) CRGDK, an RGD sequence for targeting αvβ3 integrins in the tumor extracellular matrix,250 2) CREKA for targeting the tumor vasculature,251 and 3) TAT to target the nucleus252 (Figure 19). This evidence concerns the gene HDAC9 and neoplasm.