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Cytogenetic study of maturing granulocytes in bone marrow of patients with acute myelogenous leukemia
M R Baer1, C Sreekantaiah, S N Jani Sait
1Department of Hematologic Oncology, Roswell Park Memorial Institute, Buffalo, NY 14263.
Abstract:
To determine the cytogenetic origin of maturing granulocytes in the bone marrow of patients with acute myelogenous leukemia, bone marrow cells were studied using a modified cytogenetic technique, which does not disrupt the cell membrane, in conjunction with periodic acid-Schiff (PAS) staining. In four cases successfully studied, myeloblasts were PAS-negative and granulocytes were PAS-positive. In three cases successfully studied following 0-2 days of culture, metaphase spreads with abnormal karyotypes characteristic of the patients' leukemic clones were seen in five of five, six of nine, and four of four PAS-positive cells successfully studied. These patients' bone marrows were AN, AA, and AA, respectively, by standard cytogenetic study. Therefore, the cytogenetic status of PAS-positive cells did not necessarily correlate with presence or absence of normal metaphases determined by standard cytogenetic study. Bone marrow cells which underwent full and partial granulocytic maturation in suspension culture were studied following 2 weeks of culture. Abnormal karyotypes were seen in five of five and two of two metaphases in PAS-positive cells successfully studied in two patients. Therefore, we have demonstrated that when acute myelogenous leukemia cells undergo myeloid maturation in culture, the mature cells may be definitely proven to derive from leukemic progenitors rather than from normal stem cells.
Insights
This study demonstrates that mature granulocytes in acute myelogenous leukemia bone marrow originate from leukemic cells. Using modified cytogenetics and PAS staining, researchers confirmed mature cells derived from abnormal progenitors, not normal stem cells.
Area of Science:
- Hematology
- Oncology
- Cytogenetics
Background:
- Acute myelogenous leukemia (AML) is characterized by the proliferation of myeloid blasts.
- Determining the cellular origin of mature myeloid cells in AML is crucial for understanding disease pathogenesis.
Purpose of the Study:
- To ascertain the cytogenetic origin of maturing granulocytes in AML bone marrow.
- To differentiate between leukemic and normal stem cell contributions to myeloid maturation in AML.
Main Methods:
- A modified cytogenetic technique preserving cell membranes was employed.
- Periodic acid-Schiff (PAS) staining was used to differentiate cell types.
- Bone marrow cells were cultured to observe myeloid maturation.
- Karyotyping was performed on PAS-positive cells at various culture time points.
Main Results:
- Myeloblasts were PAS-negative, while maturing granulocytes were PAS-positive.
- Abnormal karyotypes, characteristic of leukemic clones, were identified in PAS-positive maturing granulocytes.
- These abnormal karyotypes persisted in mature granulocytes after extended culture, confirming their leukemic origin.
Conclusions:
- Mature granulocytes in AML patients can be definitively shown to derive from leukemic progenitors.
- The study provides strong evidence against normal stem cell contribution to myeloid maturation in the context of AML.
- This finding has implications for understanding AML biology and potential therapeutic strategies.