SET and neoplasm: To validate I2PP2A/SET as a target of FTY720 for its tumour suppressor roles, we determined the effects of FTY720 on cell death and/or tumour suppression in response to shRNA-mediated knockdown of I2PP2A and its reconstitution in A549/sh-I2PP2A/SET versus A549/sh-I2PP2A/SET-WT-I2PP2A/SET cells in situ and in vivo.