CD8A and cancer: In fact, ZSTK474 doses (100 mg/kg) that were sufficient to deplete Tregs and generate memory CD8+ T cells were much lower than those (400 mg/kg) aiming at directly killing cancer cells.49 We have recently reported that tyrosine kinase inhibitors such as imatinib also deplete Tregs through targeting TCR signaling.50 Importantly, as appropriate T cell activation was achieved in lower doses in both the PI3K inhibitor ZSTK474 and tyrosine kinase inhibitors than the maximum tolerated dose, the dosage used as anticancer reagents may not be optimal for ‘cancer immunotherapy reagent’.