Internal tandem duplication of flt3 gene in Egyptian pediatric acute myeloid leukemia and acute lymphoblastic leukemia

Abstract EN

Objective : to study internal tandem duplication of FLT3 gene in Egyptian pediatric AML and ALL and its correlation to prognostic factors as well as clinical outcome.

Methods : we examined 152 newly diagnosed acute leukemia cases including 69 AML and 83 ALL by genomic PCR.

We correlated tandem duplication of FLT3 to age, sex, TLC, FAB, immunophenotypic subtypes and induction of remission.

Results : tandem duplication was found in 14 / 69 (20.3 %) AML cases: M1 7 / 24, M2 1 / 14, M3 4 / 13, M4 0/8 and M5 1 / 4.

Ten of the cases with duplication were males, 8 cases were in the high-risk age group [< 2 and ≥ 10] and 6 cases had TLC ≥ 50 x 109 / L.

Failure to achieve induction remission was 62 % in cases with duplication vs.

31.7 % in cases without duplication, also 37.5 % vs.

14.6 % of cases respectively remained refractory to therapy.

Tandem duplication was found in 6 / 83 (7.2 %) ALL cases: 2 cases were precursor-B and 4 were T-ALL.

Four cases with duplication were in the high-risk age group and 3 cases had TLC ≥ 50 x 109 / L.

Tandem duplication of FLT3 did not show an impact on induction remission rate in ALL.

Conclusion : FLT3 / ITD in our pediatric AML cases (20.3 %) was much higher than that reported in literature (5.3 %-11 %).

It was as high as that reported in adults (20-23 %).

It was identified as a poor prognostic factor in pediatric AML as regards remission rate.

FLT3 / ITD was reported for the first time in classical ALL (7.4 %).

Further study on a larger scale is recommended.