MTOR and central nervous system cancer: Hence, to investigate the possible link between sCPE, RPS6 and Rac1 in glioma, we performed further functional analysis of the active (GTP-bound) form of Rac1 in the LNT229 cell line upon sCPE-overexpression as well as in LN18 cells, in which CPE was stably knocked down, with and without inhibition of mTOR.