Comparison of the algorithms classifying the ABC and GCB subtypes in diffuse large B-cell lymphoma

Area of Science:

• Hematology
• Oncology
• Immunology

Background:

• Diffuse large B-cell lymphoma (DLBCL) comprises activated B-cell (ABC) and germinal center B-cell (GCB) subtypes, requiring accurate classification.
• Standardized immunohistochemical algorithms for DLBCL subtyping are inconsistently applied across laboratories.
• Understanding subtype-specific antigen expression may impact treatment strategies.

Purpose of the Study:

• To evaluate and compare four distinct immunohistochemical algorithms (Hans, modified Hans, Choi, modified Choi) for DLBCL subtyping.
• To assess the prognostic significance of these algorithms for overall survival (OS) in DLBCL patients treated with CHOP-like regimens.
• To investigate CD19 and CD20 antigen expression differences between ABC and GCB subtypes.

Main Methods:

• Retrospective analysis of 127 DLBCL patients treated with rituximab-CHOP or similar regimens.
• Preparation of multi-tumor tissue microarrays tested using four different immunohistochemical algorithms.
• Flow cytometric quantification of CD19 and CD20 expression in a subset of 39 patients.

Main Results:

• The Choi algorithm demonstrated prognostic value for OS, classifying patients into the GCB subgroup with a Hazard Ratio (HR) of 0.91.
• No significant difference in CD19 antigen expression was observed between ABC and GCB subtypes.
• The ABC subtype exhibited significantly decreased CD20 antigen expression compared to the GCB subtype.

Conclusions:

• The Choi algorithm is a reliable method for classifying DLBCL subtypes and predicting patient outcomes.
• CD20 expression levels may serve as a potential biomarker differentiating DLBCL subtypes.
• Further research into subtype-specific therapeutic targets is warranted.