For comparison, two FDA-approved antibodies, Cetuximab, a monoclonal antibody against EGFR for treatment of various cancers, has a Kd of 0.38 nM [61], and Trastuzumab (i.e., herceptin), a recombinant antibody against HER2, has a Kd of ~5–9 nM [62]. Here, EGFR is linked to cancer.