We first investigated the binding specificity of CD117×CD3 BTCE and found that in vitro CD117×CD3 BTCE binds to TF-1 cells, an AML cell line that expresses the CD117 receptor and lacks CD3 expression, but not to RPMI-8226 and U937 cells, two hematopoietic cell lines that do not express either CD117 or CD3 (figure 1B). Here, KIT is linked to acute myeloid leukemia.