Specific data remains rather limited about the receptor-mediated-endocytosis of covalent immunochemotherapeutics like epirubicin-[anti-HER2/neu][66,85,102] epirubicin-[anti-EGFR],[66] gemcitabine-[anti-HER2/neu],[97,98] or gemcitabine-[anti-EGFR] following their physical binding to the trophic receptors, EGFR or HER2/neu over-expressed by mammary adenocarcinoma (SKBr-3). The gene discussed is EGFR; the disease is breast adenocarcinoma.