A preparation of autologous T-lymphocytes genetically engineered with a chimeric antigen receptor (CAR) specific for the tumor-associated antigen FMS-like tyrosine kinase 3 (FLT3; CD135; STK1; FLK2), with potential immunostimulating and antineoplastic activities. Upon administration, the anti-FLT3 CAR T cells AMG 553 target and bind to tumor cells expressing FLT3, which results in the cytotoxic T-lymphocyte (CTL)-mediated cell killing of FLT3-expressing tumor cells. FLT3, a class III receptor tyrosine kinase (RTK), is overexpressed or mutated in most B-lineage neoplasms and in acute myeloid leukemias (AMLs).