CD10, BCL6, and MUM1 expression in diffuse large B-cell lymphoma on FNA samples

Area of Science:

• Hematopathology
• Oncology
• Cytopathology

Background:

• Diffuse large B-cell lymphoma (DLBCL) classification into germinal center B (GCB) and non-GCB subtypes is crucial for prognosis.
• Gene expression profiling and immunohistochemistry (IHC) using CD10, BCL6, and MUM1 are standard for subtyping.
• Fine-needle aspiration (FNA) is vital for lymphoma diagnosis, sometimes being the sole available specimen.

Purpose of the Study:

• To evaluate the efficacy of CD10, BCL6, and MUM1 immunocytochemical (ICC) staining on FNA samples.
• To compare ICC performance between cell blocks (CB) and conventional smears (CS) derived from FNA.
• To validate ICC findings against established histological IHC data.

Main Methods:

• Analysis of 38 consecutive DLBCL cases diagnosed via FNA.
• Preparation of both cell blocks (CB) and conventional smears (CS) from FNA specimens.
• Application of the CD10, BCL6, and MUM1 algorithm for ICC and comparison with histological IHC in 24 cases.

Main Results:

• Successful ICC staining was achieved in 33 out of 38 FNA cases (18 CB, 15 CS).
• The CD10-BCL6-MUM1 algorithm accurately subclassified DLBCL into GCB (9 cases) and non-GCB (24 cases).
• ICC results demonstrated strong concordance with histological IHC findings.

Conclusions:

• CD10, BCL6, and MUM1 ICC staining is feasible and reliable on FNA specimens.
• Both cell blocks (CB) and conventional smears (CS) are effective for ICC analysis in DLBCL subtyping.
• ICC on FNA samples provides results comparable and equally effective to traditional immunohistochemistry on tissue biopsies.