FLT3 and leukemia: Furthermore, positive correlations were observed between the FLT3-ITD MR and the levels of the CXCR4 and Pim-1 mRNAs in leukemia cells using the Pearson correlation analysis (r = 0.693, P ≤ 0.0001; r = 0.587, P ≤ 0.0001, respectively), and between the expression of the CXCR4 mRNA and Pim-1 mRNA (r = 0.726, P ≤ 0.0001).