EGFR and brain neoplasm: For instance, branched aptamer-drug conjugates composed of various OGN sequences, enzymatically-cleavable linkers and payloads, can be illustrated by the system composed of the 46 DNA bases aptamer targeting the GR-20 region of the overexpressed epidermal growth factor receptor (EGFR) in brain tumors, the payload monomethylauristatin E, the cathepsin-cleavable ValCit-p-aminobenzylcarbamate linker and the branching situs pentaerythritol-based tetraazide, that can encapsulate different drugs [84].