Tissue microarray is inappropriate for analysis of BCL6 expression in diffuse large B-cell lymphoma

• Objective: In this study, our aim was to investigate how different immunohistochemical techniques may influence the result of BCL6 positivity and categorization in germinal center (GC) and non-GC derived diffuse large B-cell lymphoma (DLBCL), as it has been proposed that classification of DLBCL according to cell-of-origin by immunohistochemistry may be performed as a routine procedure in the diagnostic work-up. However, a number of technical issues need to be solved before introducing this as a standard technique. Methods: Tumor specimens from 122 patients with de novo stage II–IV disease, adequately treated with anthracycline-containing chemotherapy regimens were collected. Immunohistochemical expression of BCL6, CD10, and MUM-1/IRF4 was examined using a tissue microarray (TMA) technique. BCL6 and CD10 were also evaluated on whole tissue sections. Results: Due to profound tissue heterogeneity, BCL6 showed a wide range of positivity, with a high number of false negative results by TMA (25% positive), compared to 53% on whole tissue sections (WTS). CD10 was more homogeneously expressed, and TMA results corresponded better to WTS. Consequently, the results from categorization into GC and non-GC DLBCL differed considerably by use of the two methods, and resulted in very different outcome in terms of overall survival. Conclusion: Immunohistochemical GC-status determined on TMA is not reliable enough to be used for individual treatment decisions in DLBCL, mostly due to difficulties in interpreting BCL6 status.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Hematologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Hematology (hsv//eng)

Keyword

BCL6

diffuse large B-cell lymphoma

immunohistochemistry

tissue microarray

MEDICINE

MEDICIN

bCL6

microarray

tissue

diffuse large B-cell lymphoma

immunohistochemistry

Publication and Content Type

ref (subject category)

art (subject category)