Expression of RGS2 in primary bone marrow of AML patients. (A) Bone marrow samples from 84 AML patients were analyzed for RGS2 expression by real-time RT-PCR and compared with RGS2 levels in bone marrow from healthy donors. Box plots are shown for the relative expression levels of RGS2 normalized to GAPDH. The differences in expression between leukemic samples from patients with and without Flt3-ITD as well as between leukemic samples and normal bone marrow were statistically significant (P < .05, Mann-Whitney U test). (B) Another set of 120 AML bone marrow samples (49 with Flt3-WT, 50 with Flt3-ITD, and 21 with point mutations of codon 835 or 836) was analyzed for RGS2 expression compared with bone marrow of healthy donors and with CD34⁺ progenitor cells. (C) Comparison of RGS2 mRNA levels between AML samples with and without Flt3 mutation (ITD or point mutation) from the second cohort. (D) RGS2 mRNA expression in AML samples with Flt3-WT compared with Flt3-ITD with high expression of the mutated allele and to cases containing a codon 835/836 point mutation. Statistic analyses were performed with Mann-Whitney U tests. The horizontal lines indicate the median; the boxes, the interquartile range; and the error bars, the extreme values of each cohort.