BCL-6 immunostaining of normal and neoplastic lymphoid cells.

(A) BCL-6 expression in germinal centers in a lymph node showing follicular hyperplasia. (B) Diffuse large B-cell lymphoma. At left is a section stained with hematoxylin and eosin, and at right is a sample with BCL-6 immunostaining showing strong nuclear expression. (C) A trapped germinal center in a mantle lymphoma is BCL-2 negative (left) and BCL-6 positive (right). (D) BCL-6 expression by a popcorn/L&H cell (arrow) in nodular lymphocyte predominance HD (APAAP technique in paraffin sections; reproduced with permission from American Journal of Pathology106). Original magnification A, × 100; B left, × 800; B right, × 800; C left, × 200; C right, × 200; D, × 800.