Gemcitabine-(C4-amide)-[anti-HER2/neu] at the gemcitabine-equivalent concentrations of 10-7 M or 10-6 M during a 182-hour incubation period did not exert substantially greater selectively “targeted” anti-neoplastic cytotoxicity against chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3) compared to gemcitabine alone (Figures 4, 7 and 8). Here, ERBB2 is linked to breast adenocarcinoma.