CASC3 and proximal spinal muscular atrophy: Even though BTZ, like other agents, has a low blood-brain barrier (BBB) permeability for treating neurological disorders and spinal muscular atrophy [158,159,160,161,162], recent advances in the delivery method of BTZ improved anti-tumor efficacy by bypassing the BBB, making BTZ a more affordable, effective treatment for GBM [163].