Cd79a

Hematoxylin and eosin staining and IHC studies were performed on formalin-fixed and paraffin-embedded tissue sections using standard methods. Primary antibodies against CD20, CD79a, PAX-5, CD38, CD138, and MUM1 (Ventana Medical Systems, USA) were applied on a BenchMark XT automated immunostainer (Ventana Medical Systems) with Cell Conditioning heat retrieval solution (Ventana Medical Systems). Appropriate internal controls (lymphocytes) and external controls (tonsils) were also included in each section. The morphology and IHC results were reviewed by two pathologists (Wan and Yu).
Detection of EBV-encoded small RNA (EBER)-1/2 was performed with proper controls using an ISH kit (Triplex International Bioscience, China) following the manufacturer’s instructions.

Immunohistochemical stains were performed on paraffin-embedded sections of the lymph node and/or extranodal tumor biopsies using Bond-maX autostainer (Leica Microsystems, Australia) according to the manufacturer’s protocol. Mouse anti-human CD3, CD5, CD20, CD79a, BCL2, BCL6, Ki-67, and TdT (Ventana Medical Systems®, Oro Valley, AZ) were used as the primary antibodies. Horseradish peroxidase-labeled rabbit anti-mouse polyclonal antibodies were employed to convert the chromogen substrate. All stains were performed with appropriate positive and negative controls.