RAF1 and malignant glioma: Our previous study has already demonstrated that PEG-PCL-Tat could deliver the siRNA to the brain within 15 min (Olfactory bulb) to 60 min (whole brain) by intranasal administration through the olfactory nerve and trigeminal nerve pathway after across the nasal mucosal epithelial barrier [25,27], and further showed the therapeutic effects in rats with malignant glioma orthotropic implantation using anti-Raf-1 siRNA [26].