ERBB2 and breast carcinoma: An example is human epidermal growth factor-2 receptor (HER2), which has long been the main target for introducing therapeutic genes in the HER2-enriched breast cancer subtype using polyplexes or lipoplexes that contain a recombinant humanized monoclonal antibody or a single-chain antibody fragment to HER2 as ligands [2]–[4].