Abstract
Treatment outcome in patients with AML is determined by a variety of prognostic factors such as WBC, LDH, age, presence of chromosomal aberration. Recently, two acquired genetic alterations, internal tandem duplications (ITD) and Asp835 codon mutations of the fms-like tyrosine kinase 3 (FLT3) gene were reported in AML as prognostic factors. 66 consecutive adult patients (39 females and 27 males) were treated with newly diagnosed AML in our institute between January 2002 and June 2004. The median age of onset was 49±15 (range 17–83) years. The gender distribution was 1.44 (female/male). We analyzed FLT3 ITD and Asp835 mutations at the time point of diagnosis by fluorescent PCR and PCR-RFLP methods. ITD was present in 22.7% (15/66) of the patients and Asp835 mutations were detected in 7.6 % (5/66). Two patients carried both mutations. 13 of 15 ITD-positive patients had myelomonocytic or monocytic leukemia (M4 and M5 in the FAB classification system). There was no difference between the numbers of ITD-positive and negative patients in complete remission (10/15 [66.7%] vs. 31/51 [60.8%]). In the ITD-positive patient group, the relapse rate was increased (5/15 [33.3%] vs. 7/51 [13.7%]) however, this difference was statistically not significant. The age of onset was greater than 40 years in all Asp835 mutation-positive patients and in this group, no relapse occurred within the follow-up time. The remission rate (4/5) of this group was high in spite of the old age of onset. The single Asp835-positive patient also carried the ITD mutation and showed primary resistance. Our results are in agreement and confirm earlier observations for the ITD mutation in a different patient population. In our relatively small patient group the Asp835 mutation seemed to have a beneficial effect.
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