Expression of MALT1 in normal human lymphoid tissues. Sections of normal reactive tonsil (panel A), spleen (panel B), and thymus (panel C) were stained with antibodies against MALT1. The germinal center (GC) of the tonsil, the white pulp (WP) and red pulp (RP) of the spleen, and the medulla (M) and cortex (C) of the thymus are indicated. The same staining was performed with sections of gastric MALT lymphoma (panel D), follicular lymphoma (panel E), and diffuse large B-cell lymphoma (DLBCL; panel F). Images were acquired as described in “Immunohistochemical staining.”