A study demonstrates that Glioblastomas acquire resistance to radiation via upregulation of acid ceramidase (ASAH1) and sphingosine‑1-phosphate (Sph-1P). Moreover, inhibition of ASAH1 and Sph-1P, either with humanized monoclonal antibodies, small molecule drugs (i.e. carmofur), or a combination of both, led to suppression of Glioblastoma cell growth. These results suggest that ASAH1 and Sph-1P may be excellent targets for the treatment of new Glioblastomas and recurrent Glioblastomas, especially since the latter overexpresses ASAH1 ¹⁾.