Thus, strategies have been developed for particles to actively target the tumor site by tagging them with molecules able to recognize ligands within the peripheral vascular bed (e.g., vascular endothelial growth factor (VEGF) receptor22), the extracellular matrix23 or on the surface of cancer cells (e.g., folate receptor,24 epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2)25, 26). This evidence concerns the gene ERBB2 and cancer.