Comparison of germinal center markers CD10, BCL6 and human germinal center-associated lymphoma (HGAL) in follicular lymphomas

Abstract

Background: Recently, human germinal center-associated lymphoma (HGAL) gene protein has been proposed as an adjunctive follicular marker to CD10 and BCL6.

Methods: Our aim was to evaluate immunoreactivity for HGAL in 82 cases of follicular lymphomas (FLs)--67 nodal, 5 cutaneous and 10 transformed--which were all analysed histologically, by immunohistochemistry and PCR.

Results: Immunostaining for HGAL was more frequently positive (97.6%) than that for BCL6 (92.7%) and CD10 (90.2%) in FLs; the cases negative for bcl6 and/or for CD10 were all positive for HGAL, whereas the two cases negative for HGAL were positive with BCL6; no difference in HGAL immunostaining was found among different malignant subtypes or grades.

Conclusions: Therefore, HGAL can be used in the immunostaining of FLs as the most sensitive germinal center (GC)-marker; when applied alone, it would half the immunostaining costs, reserving the use of the other two markers only to HGAL-negative cases.

Figure 1

"In situ" follicular neoplasm. The follicle depicted in serial sections shows partial polarization loss and prevalence of small cells (a), all staining for CD10 (b), strongly for BCL2 (c) and for HGAL (d).

Figure 2

Invasive follicular lymphoma. FL is formed by large nodules with interfollicular invasion (a) showing positive staining for CD10 (b), BCL6 (c), HGAL (d); the positivity for GC markers are more evident in the nodular component than in the interfollicular areas in this case. BCL2 was moderately and partially expressed (e). Ki67 proliferative index was high (f).