EGFR and neoplasm: Morys and colleagues post-modified core pDNA lipo-polyplexes with sequence-defined mono- or bivalent Cys(Npys)2-PEG24-GE11 via disulfide formation, the resulting post-functional lipo-polyplexes exhibited receptor-dependent internalization as well as luciferase marker gene and sodium iodide symporter (NIS) gene expression in epidermal growth factor receptor (EGFR)-overexpressing tumor cells.