Moreover, αCD33-mAB-P/P-siRNA complexes internalized efficiently and specifically into CD33-positive OCI-AML2, OCI-AML3 and KG1 AML cells (Fig. 1L-N and P-R), whereas CD33-negative OCI-Ly19 DLBCL cells did not internalize αCD33-mAB-P/P-Alexa488-control-siRNA complexes (Fig. 1O and S). Here, CD33 is linked to acute myeloid leukemia.