AML1-ETO-positive acute myeloid leukemia presents different phenotype in
pediatric and adult patients
Background: C-KIT mutation and extramedullary infiltration highly occur
in AML1-ETO-positive acute myeloid leukemia (AE-AML). Whether they
having the same clinical significance in pediatric and adult patients
remains unsure. Procedure: Totally 75 pediatric and 98 adult patients
with newly diagnosed AE-AML from 5 centers were included and analyzed.
Results: The incidence of extramedullary leukemia (EML) (13.3% vs.
29.6%, P=0.008) and c-KIT mutations (12/68, 17.6% vs. 30/74, 40.5%,
P=0.003) in pediatric patients were less than half compared to adult
counterpart. The disease outcome including complete response (CR),
disease-free survival (DFS) and overall survival (OS) was comparable
between the two patient groups, when induction/consolidation regimens
were taken into consideration. Based on multivariate analysis, EML was
associated with a higher relapse and worse survival, and patients
carrying c-KIT mutations showed a trend toward a worse prognosis.
Grouping by age, the adverse effect of EML and c-KIT mutations on
prognosis was only seen in adults but not children and was not affected
by consolidation regimens. Conclusions: The occurrence of EML and c-KIT
mutations was much less in pediatric than adult AE-AML. Both EML and
c-KIT mutations adversely impacted the disease outcome in adult but not
pediatric patients, suggesting the behavior of AML1-ETO fusion protein
might be age-dependent.