Expression of the oncogenic AML proteins leads to reduced CD48 mRNA levels. (A-D) qRT-PCR and FACS analysis of U937 cells transduced with PML3 (A), RARA (B), AML1b (C), and ETO (D). Left graphs: Verification of the overexpression of the single proteins by qRT-PCR. The results were normalized to hypoxanthine guanine phosphoribosyl transferase (HPRT). Error bars represent the standard deviation of the means of 3 independent experiments (each in triplicates). Left histograms (labeled GFP): Flow cytometry of GFP expression (indicative of the transduction) of untransduced U937 cells (gray line) and transduced cells (black line). Right histograms (labeled CD48): Flow cytometry analysis of CD48 expression in cells transduced with 1 of the single proteins (black line) or with an empty vector (gray line). The gray shaded histograms are the background staining with an isotype-matched control antibody. The FACS staining includes 1 representative experiment of 2 representative experiments performed. (E) qRT-PCR analysis of the expression of CD48 in U937 cells transduced with an empty vector compared with U937 transduced with PML-RARA or AML1-ETO. The results were normalized to the expression of HPRT. The relative copy number of CD48 in cells expressing the empty vector was defined as 1. Error bars represent the standard deviation of the means of 3 independent experiments (each in triplicates). **P < .01; ***P < .001, Student t test.