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Updated: Aug 8, 2026
Flow Cytometry to Estimate Leukemia Stem Cells in Primary Acute Myeloid Leukemia and in Patient-derived-xenografts, at Diagnosis and Follow Up
Published on: March 26, 2018
Analysis of acute myeloid leukemia cells by flow cytometry, introducing a new light-scattering classification
N Harada1, S Okamura, A Kubota
1First Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Insights
Flow cytometry light scattering (LSC) classifies acute myeloid leukemia (AML) cells into three types. LSC patterns correlate with immunophenotype, aiding in precise AML diagnosis and maturation stage assessment.
Area of Science:
- Hematology
- Oncology
- Flow Cytometry
Background:
- Acute myeloid leukemia (AML) is a heterogeneous cancer requiring precise classification.
- Current classification relies on morphology and immunophenotype, but further refinement is beneficial.
Purpose of the Study:
- To evaluate the utility of light-scattering characteristics in conjunction with immunophenotyping for AML classification.
- To correlate light-scattering classification (LSC) types with French-American-British (FAB) classification and surface marker expression in AML.
Main Methods:
- Flow cytometry was used to analyze light-scattering properties (forward scatter - FSC, side scatter - SSC) and immunophenotype (surface markers like CD7, CD34, CD33) of AML cells from 71 patients.
- AML cases were categorized into three LSC types (A, B, C) based on FSC and SSC patterns relative to lymphocytes and monocytes.
- LSC types were compared with FAB classification and the expression of specific surface antigens.
Main Results:
- Three LSC types were identified: Type A (58% of cases), Type B (25%), and Type C (17%).
- CD7, an immature marker, was more frequent in LSC Type A and FAB M1 cases. CD7 was absent in Type C.
- FAB M1 cases showed high CD34 expression (72%), while CD33 and CD34 showed a negative correlation in FAB M2 cases.
Conclusions:
- Light-scattering pattern analysis via flow cytometry offers a complementary approach to immunophenotyping for AML.
- LSC classification may provide insights into the maturation stage of leukemic cells, potentially refining AML diagnosis.
- Scattergram patterns can aid in distinguishing AML subtypes and understanding disease heterogeneity.
Abstract:
A combined flow-cytometric evaluation of light scattering and the immunophenotype of acute myeloid leukemia (AML) cells from 71 newly diagnosed consecutive patients was conducted. Light-scattering characteristic of AML cells examined by flow cytometry and multiple surface markers were also analyzed using the same samples, to enable a comparison with the French-American-British (FAB) classification. Our AML cases could be classified into three light-scattering classification (LSC) types according to their physical properties on flow cytometry. These were type A, where forward light scattering (FSC) of the leukemic cell population was larger than that of lymphocytes, while side light scattering (SSC) was the same or larger than that of lymphocytes but smaller than that of monocytes; type B, where FSC of the leukemic cell population was larger than that of lymphocytes and SSC spread toward that of monocytes; and type C, where both FSC and SSC of the leukemic cell population spread beyond those of monocytes. Although a clear relationship between the FAB classification and LSC classification by the light-scattering profile of AML was not established, we observed the following findings. The majority of cases were classified as type A (58%), while type B comprised 25% and type C comprised 17%. While CD7 expression on AML cells is considered to be an immature characteristic, CD7 was expressed more frequently among LSC type A cases. Furthermore, all but one of the FAB M1 cases were classified as type A. On the other hand, CD7 was not expressed on type C leukemic cells. The percentage of cases in which more than 60% of leukemic cells possessed another immature surface antigen, CD 34ö, was 13/18 (72%) among FAB M1 cases, much higher than among FAB M2 (35%) or FAB M4 (27%) cases. A negative correlation was observed between mature antigen CD33 and CD34 among the FAB M2 cases. The frequency of CD7 expression was 25% among the total cases, and CD7-positive cases were frequent among FAB M1 and M2, but not among FAB M3 cases. These findings concerning LSC and immunophenotyping indicate that the scattergram pattern analysis may contribute towards more precise immunophenotyping, in that it reflects the maturation stage of each AML case.
