[1] MIT, Dept Chem, Cambridge, MA 02139 USA
[2] MIT, Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA
[3] Harvard Med Sch, Brigham & Womens Hosp, Harvey Cushing Neurooncol Labs, Dept Neurosurg, Boston, MA 02115 USA
[4] Univ Cologne, Fac Med, Dept Neurosurg, Ctr Neurosurg, D-50937 Cologne, Germany
[5] Univ Cologne, Univ Hosp, D-50937 Cologne, Germany