CASP9 and cancer: Alternatively, there are additional strategies to obviate the possible toxicities associated with the presence of L1-CAM in normal tissues when using CAR-based T cell therapy in treating cancer, including the use of mRNA transfection-based gene transfer approaches rather than a lentiviral delivery method for CAR introduction in T cells [47], as well as incorporation of a suicide gene strategy such as EGFRt [26] or inducible caspase-9 [48], to selectively eliminate CAR T cells in patients should adverse events occur.