Minor Myeloid Leukemic Populations in Pediatric Acute Lymphoblastic Leukemia: A Potentially Underrecognized Mixed-Phenotype Tumor?
- 1Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, 1 Samory Mashela St., Moscow 117198, Russia.
Abstract
In “bilineal” mixed-phenotype acute leukemia (MPAL), the proportions of lymphoid and myeloid leukemic cells may differ substantially. A myeloid component may constitute <10% of bone marrow (BM) cells and show subtle immunophenotypic abnormalities detectable by multicolor flow cytometry (MFC). The significance of minor myeloid leukemic populations in otherwise acute lymphoblastic leukemia (ALL), including their association with lineage switch, remains uncertain. We retrospectively reviewed diagnostic MFC data from 5094 children with B-cell precursor or T-cell ALL. An additional minor myeloid leukemic population (<10% of BM) was identified in 92 ALL cases (1.8%), with a median of 3.0% of BM cells (0.2–9.2%). The frequency of ALL cases harboring a minor myeloid leukemic population was comparable to that of overt “bilineal” MPAL (with both populations ≥ 10% of BM cells), diagnosed during the same period. The myeloid populations expressed CD33, CD64, CD14, lysozyme, and markers shared with the dominant lymphoblastic population (CD19/CD7, CD34, CD117). Common genetic findings were high hyperdiploidy (n = 14), KMT2A rearrangements (n = 13), and BCR::ABL1 (n = 8). Although no expansion was documented in most patients, 6 of 83 newly diagnosed patients (7.2%) developed lineage switch to acute myeloid leukemia or overt “bilineal” MPAL. Most cases were managed successfully with standard ALL-directed therapy.
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BibTeX
@article{semchenkova2026minor,
title = {{Minor Myeloid Leukemic Populations in Pediatric Acute Lymphoblastic Leukemia: A Potentially Underrecognized Mixed-Phenotype Tumor?}},
author = {Alexandra Semchenkova and Polina Lavrova and Vladimir Kozeev and Irina Demina and Ekaterina Mikhailova and Julia Roumiantseva and Svetlana Lagoyko and Anna Kazakova and Galina Novichkova and Alexander Karachunskiy and Elena Zerkalenkova and Alexander Popov},
journal = {International Journal of Molecular Sciences},
year = {2026},
month = oct,
doi = {10.3390/ijms27198816},
url = {https://www.mdpi.com/1422-0067/27/19/8816},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Minor Myeloid Leukemic Populations in Pediatric Acute Lymphoblastic Leukemia: A Potentially Underrecognized Mixed-Phenotype Tumor?
AU - Alexandra Semchenkova
AU - Polina Lavrova
AU - Vladimir Kozeev
AU - Irina Demina
AU - Ekaterina Mikhailova
AU - Julia Roumiantseva
AU - Svetlana Lagoyko
AU - Anna Kazakova
AU - Galina Novichkova
AU - Alexander Karachunskiy
AU - Elena Zerkalenkova
AU - Alexander Popov
PY - 2026
DA - 2026/10/02
JO - International Journal of Molecular Sciences
DO - 10.3390/ijms27198816
UR - https://www.mdpi.com/1422-0067/27/19/8816
AB - In “bilineal” mixed-phenotype acute leukemia (MPAL), the proportions of lymphoid and myeloid leukemic cells may differ substantially. A myeloid component may constitute <10% of bone marrow (BM) cells and show subtle immunophenotypic abnormalities detectable by multicolor flow cytometry (MFC). The significance of minor myeloid leukemic populations in otherwise acute lymphoblastic leukemia (ALL), including their association with lineage switch, remains uncertain. We retrospectively reviewed diagnostic MFC data from 5094 children with B-cell precursor or T-cell ALL. An additional minor myeloid leukemic population (<10% of BM) was identified in 92 ALL cases (1.8%), with a median of 3.0% of BM cells (0.2–9.2%). The frequency of ALL cases harboring a minor myeloid leukemic population was comparable to that of overt “bilineal” MPAL (with both populations ≥ 10% of BM cells), diagnosed during the same period. The myeloid populations expressed CD33, CD64, CD14, lysozyme, and markers shared with the dominant lymphoblastic population (CD19/CD7, CD34, CD117). Common genetic findings were high hyperdiploidy (n = 14), KMT2A rearrangements (n = 13), and BCR::ABL1 (n = 8). Although no expansion was documented in most patients, 6 of 83 newly diagnosed patients (7.2%) developed lineage switch to acute myeloid leukemia or overt “bilineal” MPAL. Most cases were managed successfully with standard ALL-directed therapy.
SN - 1422-0067
ER -