For example, more specific targeting of tumors can be achieved by conjugating tumor-specific recognition molecules such as transferrin, folic acid, epidermal growth factor (EGF), or any number of monoclonal antibodies to the surface of GNPs (El-Sayed et al., 2005; Chithrani et al., 2006; Eghtedari et al., 2009). Here, EGF is linked to neoplasm.