For example, when tested in protein synthesis inhibition assays, scFv(FRP5)-ETA displayed an IC50 value towards SKBR3 breast carcinoma cells of 29 ng/ml [9], compared with a value of 32 ng/ml for e23(Fv)PE40, an ErbB2-specific molecule employing a scFv antibody fragment of e23 for cell targeting [20]. The gene discussed is ERBB2; the disease is breast carcinoma.