FLT3-ITD DNA allelic burden, but not mRNA levels, influences the biological characteristics of AML patients

FMS-like tyrosine kinase 3 gene internal tandem (FLT3-ITD) mutations represent one of the most frequent genetic lesions in acute myeloid leukemia (AML) and imparts a negative prognostic. For an optimal patient management, current clinical guidelines recommend the evaluation of the allelic ratio (AR), expressed as the DNA FLT3-ITD/WT mutational burden. We sought to evaluate the differences between the AR and FLT3-ITD/WT mRNA ratio (RR) and their respective impact on the biological characteristics of AML patients. A total of 32 DNA and mRNA samples from AML patients with FLT3-ITD were evaluated. There was a good correlation between the AR and RR (Spearman’s rho= 0.652, P <0.001). None of the biological characteristics were influenced by the RR values, whereas patients with high AR values (≥0.5) had higher WBC counts (Mann-Whitney, P= 0.01), LDH levels (Mann-Whitney, P= 0.037), and circulating blasts levels (Mann-Whitney, P= 0.023) than patients with low AR values (