CASP8 and central nervous system cancer: In addition, the previous researches had also shown cytokine neuregulin 1 (Nrg1) could upregulate the L1CAM expression to enhancing the migration of glioma cells [30], and TGF-β1 could mediate L1CAM expression, then led to the downregulation of caspase-8 and apoptosis resistance [3].