HRAS and glioblastoma: Lastly, a GBM model was obtained in the tree shrew Tupaia belangeri, which is phylogenetically closer to primates than rodents: a LV was used to transduce mutant H-Ras and a shRNA to silence p53, resulting in the fast development of tumors with histological features reminiscent of GBM, including aggressiveness and GBM histological features [105].