Validation of genes overexpressed in GEP by immunohistochemistry. Representative HSTL disclosed staining of neoplastic cells for FOSB (A), SYK (B), CD56 (C), BCL10 (D), GSTP1 (E), and PRDM1 (F-G). Panel G shows DERL2 cells. The inset of panel A illustrates FOSB-positive cells (brown) also expressing TIA1 (red). Staining of scattered reactive cells positive for granzyme H is seen (H). Images were captured with a Zeiss Axioskop2 microscope (Zeiss). Photographs were taken with an Olympus DP70 camera. Images were acquired with Olympus DP Controller 2002 and images were processed with Adobe Photoshop Version 7.0. Original magnification, 400× (A-H).