Abstract
BACKGROUND: Acute erythroid leukemia (AEL) is a rare subtype of acute myeloid leukemia (AML) that represents less than 5% of AML in children. However, its clinical picture is not fully understood.
PATIENTS & METHODS: We conducted a retrospective analysis on AEL using data from the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) AML-05 study (registered at http://www.umin.ac.jp/ctr/index.htm as UMIN000000511) in which patients were enrolled between 2006 and 2010. Morphological, immunophenotypic, cytogenetic, and molecular diagnoses were confirmed by the integrated prospective central diagnostic system.
RESULTS: Among the 443 children (age 0 to 18 years old at diagnosis) with de novo AML (acute promyelocytic leukemia and Down syndrome patients are excluded), ten AEL patients (2.2%) were identified. All the cases were classified as M6 in French-American-British classification (eight as M6a, one as M6b, and one as M6). Notably, 8 were classified as AML with myelodysplasia-related changes (5 with morphological dysplasia and 3 with myelodysplasia-related cytogenetic abnormalities) and 2 as AEL in World Health Organization classification (ver.4). There were 6 males and 4 females. Median age and leukocyte count at diagnosis was 3.5 years old (range, 1-15 years old) and 4.7 x 109/L (1.1-16.1 x 109/L), respectively. Cytogenetically, 3 had complex karyotype, 2 had monosomy 7, and 5 had normal karyotype. Molecular analysis showed one case with NRAS mutation, one with both mutated KIT and WT1, and one with MLL-PTD. No case was FLT3 -ITD positive. Eight cases achieved complete remission after initial induction but 3-year event-free survival and overall survival rates were 30.0% (SE 14.4%) and 41.1% (SE 17.5%), respectively.
CONCLUSIONS: AEL has distinct features such as high frequency of myelodysplasia- related features and poor risk cytogenetics. Because the outcome seems poor, further genetic analysis is required for development of effective novel therapy.
No relevant conflicts of interest to declare.
Author notes
Asterisk with author names denotes non-ASH members.
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