TSN and glioblastoma: However, treating GBM with TSN is still promising due to the following: (1) TSN is able to cross the blood-brain barrier and exerts intracranial activity on neurotransmitter release and ion channels function [21]; (2) TSN elicits cytotoxicity to most cancer cells at nanomolar concentrations, which can be easily achieved by oral administration without causing obvious hepatotoxicity; and (3) GBM is usually resistant to chemotherapy, and new therapeutic options are warranted.