Identification of a new leukemia-targeting motif. (A) Binding of CGFYWLRSC-, CAYHRLRRC-, or insertless phage to ALL (T-lymphoblastic) cell lines MOLT-4 and CCRF-CEM, AML cell lines HL-60 (promyelocytic) and OCI-AML3 (myelocytic), CML cell line K562, multiple myeloma cell line RPMI-8226, and lymphoma cell lines SR-786 (T-cell lymphoma) and U937 (monocyte lymphoma), respectively. The data are averages of triplicates per assay from 2 independent experiments. *P < .05; **P < .01; and ***P < .001. (B) Comparison of internalization of phage-displaying peptides into leukemia cells. The FITC-labeled anti-phage stain is shown relative to that of the IgG isotype control. The blue color indicates the DAPI nuclear stain. Magnification, 500×.