ERBB2 and breast adenocarcinoma: Conservative speculation suggests that dual-combinations of covalent immunochemotherapeutics like gemcitabine-(C4-amide)-[anti-EGFR] with gemcitabine-(C4-amide)-[anti-HER2/neu] promote greater levels of simultaneous selective “targeted” gemcitabine delivery/membrane deposition and intracellular gemcitabine internalization at both EGFR and HER2/neu endogenous receptors than can be achieved through selective “targeted” gemcitabine delivery at only a single endogenous membrane receptor over-expressed on the exterior surface membrane of chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3).