Zhao et al. synthesized new 99mTc-labeled generation two dendrimer-entrapped gold nanoparticles (Au DENPs) conjugated with Diethylene Triamine Pentaacetic Acid (DTPA) and polyethylene glycol (PEG) modified with chemokine receptor-4 (CXCR4) ligand, FC131 peptide, based on the fact that CXCR4 is overexpressed in glioma cells and is associated with short survival [31]. This evidence concerns the gene CXCR4 and central nervous system cancer.