These ligands bind specifically to the antigen, for example, CD19 antigen and cell-surface receptors, including human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR), transferrin, sigma receptors, VEGF receptors, folate receptors, and glycoprotein receptors expressed on the tumor cell surface [72]. This evidence concerns the gene ERBB2 and neoplasm.