EPHB4 is expressed in AML. (A) Representative plot of 1 primary AML sample that screened positive for sensitivity to RNAi against EPHB4. This particular sample had a validated mutation in NRAS, which serves as a positive control, because AML cells demonstrate similar sensitivity to RNAi against NRAS as they do against EPHB4. *P < .05. (B) Cell surface EPHB4 expression in myeloid leukemia cell lines as measured by flow cytometry. The IgG isotype used to determine negative population is in gray. (C) Cell surface EPHB4 expression on primary AML blasts representing high (AML5), moderate (AML11), and no (AML16) expression as measured by flow cytometry. (D) Summary of EPHB4 expression on primary AML (n = 25) and normal, human CD34⁺ bone marrow cells obtained from healthy donors. Expression was measured by flow cytometry, and MFI was calculated and divided by the MFI of negative control. Results are plotted on log scale, therefore the expression ratio of 1 corresponds to no expression. The bar represents average MFI. P = .0012