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Updated: Apr 27, 2026
Immunoglobulin Gene Sequence Analysis In Chronic Lymphocytic Leukemia: From Patient Material To Sequence Interpretation
Published on: November 26, 2018
Bcl-2/IgH expression of diffuse large B-cell lymphoma cells in minimal bone marrow infiltration
Insights
Detecting Bcl-2/IgH translocation using FISH in bone marrow aids in early identification of minimal residual disease in diffuse large B-cell lymphoma (DLBCL). This method offers superior sensitivity compared to traditional morphology for minimal bone marrow infiltration.
Area of Science:
- Hematology
- Oncology
- Molecular Biology
Background:
- Diffuse large B-cell lymphoma (DLBCL) is a significant hematologic malignancy.
- Minimal bone marrow (BM) infiltration by DLBCL poses diagnostic challenges.
- The role of Bcl-2 translocation in minimal BM infiltration requires further investigation.
Purpose of the Study:
- To investigate the role of Bcl-2 translocation at chromosomal and protein levels in minimal BM infiltration by DLBCL.
- To evaluate the utility of fluorescence in situ hybridization (FISH) and immunocytochemistry (ICC) for detecting Bcl-2/IgH rearrangement in DLBCL.
- To compare the sensitivity of FISH with cytomorphology for detecting minimal BM infiltration.
Main Methods:
- FISH analysis was performed on BM and lymph node (LN) samples from 103 DLBCL patients to detect the Bcl-2/IgH fusion gene.
- Bcl-2 protein levels were quantified in BM and paraffin-embedded tissues using ICC and immunohistochemistry (IHC), respectively.
- Cytologic morphology and FISH results were compared for minimal BM infiltration detection during follow-up.
Main Results:
- Bcl-2/IgH translocation was detected in 41.7% of LN samples and 34 patients' BM samples.
- A significant positive correlation was observed between positive Bcl-2 ICC staining and t(14;18) translocation (p < 0.001).
- FISH detected Bcl-2/IgH rearrangement in 56.3% of patients earlier than cytomorphology, indicating higher sensitivity for minimal BM infiltration.
Conclusions:
- FISH assessment of Bcl-2/IgH translocation is a valuable tool for detecting minimal BM infiltration in DLBCL.
- This method can aid in the early identification of minimal residual disease and potential relapse.
- Combining FISH with cytologic morphology enhances the diagnostic accuracy for minimal bone marrow infiltration in DLBCL patients receiving treatment.
Background:
We sought to investigate the role of the Bcl-2 translocation at the chromosomal and protein levels in minimal bone marrow (BM) infiltration by diffuse large B-cell lymphomas (DLBCL).
Methods:
The presence of the Bcl-2/IgH fusion gene was detected in BM samples and paraffin-embedded lymph node (LN) samples from 103 patients with DLBCLs using FISH. Bcl-2 protein levels in BM and paraffin-embedded tissues were quantified using immunocytochemistry (ICC) and immunohistochemistry (IHC), respectively.
Results:
Bcl-2/IgH translocation in paraffin-embedded LN tissue sections was observed in 43 (41.7%) patients by FISH. Of the 43 patients, the Bcl-2/IgH rearrangement in the bone marrow specimens occurred in 34 patients. The Bcl-2/IgH recombination rate in stage III cancers was not significantly different compared to the rate observed in stage I/II cancers (p = 0.101), respectively showing no statistical differences between stage IV and I/II (p = 0.179). In 64.7% (22/34) of the cases with t(14;18), Bcl-2 was detected based on ICC analysis. Positive Bcl-2 ICC staining and the t(14;18) translocation were positively correlated (p < 0.001). We then applied our FISH method to slides with at least one abnormal cell and were subjected to FISH analysis after staining. During the follow-up, no infiltration by cytomorphology for 16 DLBCL patients whose bone marrow presented Bcl-2/IgH gene rearrangement at diagnosis, and two cases were positive by morphology compared to FISH-positive results 6 months later; 9 out of 16 patients (56.3%) presented with positive Bcl-2/IgH results earlier than the morphology evaluation after 12 months.
Conclusions:
Utilizing both FISH and cytologic morphology, the assessment of Bcl-2/IgH translocation status could contribute to the better detection of minimal bone marrow infiltration and relapse receiving treatment by DLBCL cells.
