FISH is Still an Excellent Tool to Monitor High-Grade Lymphomas

Area of Science:

• Hematology
• Oncology
• Molecular Pathology

Background:

• Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin lymphoma.
• Genetic rearrangements, particularly involving MYC, BCL2, and BCL6, are associated with poorer prognosis in DLBCL.
• Accurate classification of lymphoma subtypes is critical for treatment selection and patient outcomes.

Purpose of the Study:

• To characterize a case of lymphoma with concurrent rearrangements in MYC, BCL2, and BCL6.
• To highlight the diagnostic utility of DNA Fluorescence In Situ Hybridization (FISH) in identifying these genetic alterations.
• To emphasize the updated classification of these aggressive lymphomas as high-grade B-cell lymphomas.

Main Methods:

• Core needle biopsy and histopathological examination of lymph node tissue.
• Immunohistochemistry staining for CD20, PAX5, CD10, BCL6, BCL2, cMYC, MUM1, and Ki67.
• DNA Fluorescence In Situ Hybridization (FISH) using dual-color break-apart probes for BCL6, MYC, and BCL2 genes.

Main Results:

• The lymphoma exhibited a malignant lymphoid infiltrate positive for B-cell markers and a high proliferation index (~95% Ki67).
• FISH analysis revealed BCL6 rearrangements in 95%, MYC rearrangements in 77%, and BCL2 rearrangements in 95% of examined cells.
• The findings confirmed a triple-hit lymphoma, consistent with the classification of high-grade B-cell lymphoma with MYC, BCL2, and/or BCL6 rearrangements.

Conclusions:

• This case exemplifies a high-grade B-cell lymphoma characterized by concurrent MYC, BCL2, and BCL6 rearrangements.
• FISH analysis is essential for detecting these critical genetic alterations and refining lymphoma classification.
• Accurate identification of these triple-hit lymphomas is vital for appropriate clinical management and therapeutic strategies.