Fostamatinib displayed a higher selectivity to those cell lines with higher kinase activation or ZAP70 expression (KOPT-K1, HSB-2, JURKAT, ALL-SIL, DND-41, SUP-T13, MOLT-4) with higher sensitivity compared with CD3+ control cells (Supplemental Figure 11D). This evidence concerns the gene ZAP70 and acute lymphoblastic leukemia.