Introduction
Pediatric acute myeloid leukemia’s (AMLs) are a heterogeneous group of
diseases that can be categorized according to their morphology, lineage,
and cytogenetics. Current improvements in outcome of pediatric AML
reflect the use of intensive chemotherapy, accessibility to
hematopoietic stem cell transplantation (HSCT) as well as advancements
in both supportive care and treatment of infections in these children.
Most centers around the world manage to achieve complete remission (CR)
rates of about 80–90%, relapse rates of 30–40%, event-free survival
(EFS) rates of 50% and overall survival (OS) rates of nearly
70%.[1]
Modern-day technology has enabled the identification of relevant
cytogenetic abnormalities that can be used in clinical practice for
disease risk stratification.[2-4] In the study by Song et al.,
patients with adverse cytogenetics showed significantly poorer outcomes
than those with favorable cytogenetics.[5] Hence the prognostication
of AML with various cytogenetic abnormalities is particularly essential
for determining the optimal treatment approach for these patients.
Cytogenetic abnormalities found on chromosome 11q23 that involves the
Lysine (K)-specific MethylTransferase 2A (KMT2A), previously known as
mixed-lineage leukemia (MLL) gene rearrangements, have been seen in
about 5-11% of adult and 15-20% of pediatric AML patients.[6-8]
KMT2A has been shown to rearrange with more than 80 distinct partner
genes and this promiscuity of the oncogene leads to the heterogeneous
presentation and prognosis of the disease.[9]
To study the clinical significance of the various KMT2A rearrangements
and its impact on patient treatment outcomes we ought to analyze the
various partner genes, additional chromosomal abnormalities, time to
remission induction, treatment related mortality, types of donor and
conditioning if stem cell transplant is done and so on. Herein, we
retrospectively examined outcomes of two pediatric cohorts with AML and
KMT2A rearrangements who were treated with either chemotherapy alone or
allogeneic HSCT.