Expression of AID in MALT lymphoma and extranodal DLBCL. (A) The comparison of activation-induced cytidine deaminase (AID) mRNA expression, immunohistochemistry, and frequency of mutations is shown. Compared with centroblast mRNA AID/β-actin was expressed in all mutated evaluable MALT lymphomas and DLCBL, likewise. (B) The positive staining for AID protein in neoplastic B cells of extranodal DLBCL is shown. Images were captured with a Leica DMLB microscope (Leica, Bensheim, Germany) using a Leica PL FLUOTAR objective lens (40×/0.70) and a Leica DC200 camera. Images were imported directly into PowerPoint (Microsoft, Redmond, WA) using the Leica DC200 camera software (version 2.51).