Validation of gene expression profiling by IHC. (A,B) Case 5 showing strong cytoplasmic expression of MMP7. (A) H&E; (B) MMP7. (C,D) Case 11 showing strong cytoplasmic expression of SIGLEC6 by the tumor cells. A reactive follicle () included in the section is negative for SIGLEC6. (C) H&E; (D) SIGLEC6. (E-G) Case 14 with IGH/MALT1 translocation and spiked expression of RARA showing strong staining for MALT1 and RARA. (E) H&E; (F) MALT1 immunostain; (G) RARA. (H,I) Case 7, which lacked spiked RARA expression by gene expression profiling, is also negative for RARA by IHC. Plasma cells seen scattered through the tumor express RARA. (H) H&E; (I) RARA. All photographs were taken with a DP70 Olympus camera (Olympus, Tokyo, Japan) using an Olympus BX51 microscope (Olympus); images were acquired using DP Controller 2002 (Olympus) and processed using Adobe Photoshop version 7.0 (Adobe Systems, San Jose, CA). Original magnifications: ×100 (A,B), ×400 (C-I).