Selection of an appropriate membrane-associated antigen that is known to undergo receptor-mediated-endocytosis maximizes the active transmembrane transport of chemotherapeutic moieties in covalent immunochemotherapeutics and many carcinoma and adenocarcinoma cell types highly over-express EGFR, HER2/neu and similar membrane associated receptor sites[125]. The gene discussed is ERBB2; the disease is carcinoma.