CD33 and acute myeloid leukemia: CD33 is believed to be found predominantly on leukemic blasts of AML patients and is expressed on most AML blasts, which makes it an attractive target for chimeric antigen receptor (CAR) T cell and mAb-based therapy (Fig. 6).363 In 1992, Bernstein et al. determined that CD33− precursors isolated from AML patients who underwent long-term culture were non-clonal hematopoietic cells.364 Later, the findings of Bernstein et al. were confirmed when xenotransplantation studies showed that 99% of human AML cells that engrafted into the BM of NOD-SCID mice were CD33+.