Antibodies (anti-Her2, anti-CD44, anti-CD24), proteins (transferrins), small bioactive molecules (biotin, folate, galactose, mannose and glucose), peptides (like l-arginine glycine l-aspartic acid (RGD)) and oligonucleotides (aptamers) have been used as ligands to recognize target receptors on the tumor cells (Figure 5) [2]. Here, CD44 is linked to neoplasm.