Related Experiment Video
Updated: May 28, 2026
Isolating Malignant and Non-Malignant B Cells from lck:eGFP Zebrafish
Published on: February 22, 2019
ZAP-70 and Bcl-2 expression in B lymphoblastic leukemia cells and hematogones
Fiona E Craig1, Sara A Monaghan, Urvashi Surti
1Division of Hematopathology, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA. craigfe@upmc.edu
Insights
Bcl-2 over-expression effectively distinguishes B-lymphoblastic leukemia (B-LL) from hematogones. Zeta-associated protein (ZAP-70) shows limited utility due to lower sensitivity and variable expression in B-LL diagnosis.
Area of Science:
- Hematology
- Immunology
- Oncology
Background:
- Flow cytometric immunophenotyping is crucial for diagnosing and monitoring B-lymphoblastic leukemia (B-LL).
- Optimal reagent sets for precise B-LL blast identification are continuously sought.
- Distinguishing B-LL from normal B-cell precursors (hematogones) is essential.
Purpose of the Study:
- To evaluate the diagnostic utility of intracytoplasmic zeta-associated protein (ZAP-70) and Bcl-2 detection.
- To differentiate B-LL blasts from hematogones using these markers.
Main Methods:
- Detection of intracytoplasmic ZAP-70 and Bcl-2.
- Flow cytometric immunophenotyping of B-LL and hematogone samples.
- Comparison of antigen expression levels between B-LL and hematogones.
Main Results:
- Bcl-2 was over-expressed in 91% of B-LL cases compared to hematogones.
- Bcl-2 expression was consistently higher in CD10-bright B-LL blasts than in CD10-bright hematogones.
- ZAP-70 was over-expressed in only 30% of B-LL cases, with variable expression during therapy and between sample types.
Conclusions:
- Bcl-2 over-expression is a valuable marker for distinguishing B-LL from hematogones.
- ZAP-70 over-expression is less sensitive for B-LL detection and may require assay optimization.
- Bcl-2 shows greater clinical utility than ZAP-70 for B-LL diagnosis.
Background:
Flow cytometric immunophenotyping has an established role in the diagnosis and monitoring of B-lymphoblastic leukemia (B-LL). However, the search continues for an optimal reagent set that can identify leukemic blasts with specificity, reproducibility, and sensitivity, at any point during the course of the disease and in every specimen type.
Methods:
This study evaluated the diagnostic utility of detecting the intracytoplasmic antigens zeta-associated protein (ZAP-70) and Bcl-2 in the distinction between the leukemic blasts of B-LL and hematogones.
Results:
In comparison with hematogones in reference specimens, significantly higher levels of Bcl-2 were identified in 21 of 23 (91%) B-LL. In particular, Bcl-2 expression was consistently higher in leukemic blasts with bright intensity CD10 expression than the equivalent most immature (CD10 bright intensity) hematogones. As previously reported, Bcl-2 expression was lower in B-LL with BCR-ABL1 gene rearrangement, but the fluorescence intensity of this group of specimens was still significantly higher than that seen for hematogones. In contrast, ZAP-70 was expressed at significantly higher levels in only 7 of 23 (30%) B-LL and demonstrated other findings that might limit clinical utility, including differences in the level of ZAP-70 expression during therapy and between blasts in the peripheral blood and bone marrow.
Conclusions:
Bcl-2 over-expression provides a useful tool for the distinction between B-LL and hematogones. In contrast, although further optimization of the ZAP-70 assay might increase the sensitivity of detection, over-expression of ZAP-70 was identified in only a minority of B-LL.
