RUNX1 and leukemia: In order to assess SYK expression and activity in ETV6-RUNX1 leukemias, as a first step we evaluated three ETV6-RUNX1 cell lines (AT-1, AT-2 and REH) and two non-ETV6-RUNX1 ones (NALM-6 and RCH-ACV) (Figure 1a).