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.