Gemcitabine-(C4-amide)-[anti-HER2/neu] exerted a 41.1% maximum level of selective “targeted” anti-neoplastic cytotoxicity (58.9% residual survival) against chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3) at a gemcitabine-equivalent concentration of 10-6 M with progressive increases from 14% to 41.1% (86.0% and 58.9% residual survival) detected between 10-8 M and 10-6 M respectively (Figure 4). The gene discussed is ERBB2; the disease is breast adenocarcinoma.