PTP4A3 and neoplasm: To investigate the relationship of PRL-3 with mTOR activity, we analysed 12 sets of PRL-3-positive tumours and matched normal tissue samples from gastric cancer patients for protein expression levels of PRL-3 and phosphorylation status of Thr37/46 of 4E-BP1, a direct substrate/effector of mTOR and indicator of mTOR oncogenic activity25.