Expression of transmembrane adaptor protein PAG/Cbp in diffuse large B-cell lymphoma: immunohistochemical study of 73 cases.
PAG/Cbp is a transmembrane adaptor protein involved in proximal immune signaling. It is expressed in reactive germinal centers (GC) of secondary lymphatic follicles and related malignant lymphomas. We studied PAG/Cbp expression in GC-like and non-GC-like diffuse large B-cell lymphoma (DLBCL) subtypes. Seventy-three cases of DLBCL identified among 155 malignant lymphomas were classified as GC-like DLBCL (CD10+ or CD10-, bcl-6+, and MUM1-) and non-GC-like DLBCL (CD10-, MUM1+ or CD10-, bcl-6+, MUM1+). PAG/Cbp was detected by monoclonal antibody MEM-255 following routine immunohistochemical procedures. Thirty-five of 40 GC-like DLBCLs (88%) and 20 of 33 non-GC-like DLBCL cases (61%) expressed PAG/Cbp. Four of 12 bcl-6-negative non-GC-like DLBCL cases (33%) were PAG/Cbp positive, and only 4 of 20 bcl-6-positive non-GC-like DLBCL cases (25%) were PAG/CBP negative. All 37 FL and all 5 Burkitt's lymphomas (BL) expressed PAG/Cbp, whereas all 6 mantle cell lymphomas (MCL) and 4 of 5 chronic lymphocytic leukemias (CLL/SLL) were PAG/Cbp negative. PAG/Cbp is a reliable GC marker. Its expression correlates with GC-like DLBC phenotype in a significant majority of cases. It is typically absent in MCL and SLL/CLL.
Svec
Alexandr
A
Department of Cellular Pathology, James Cook University Hospital, Middlesbrough TS4 3BW, UK. alexandr.svec@stees.nhs.uk
D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D018858:Germinal Center / Q000378:metabolism; D006801:Humans; D016393:Lymphoma, B-Cell / Q000378:metabolism*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000378:metabolism*; D008565:Membrane Proteins / Q000096:biosynthesis*
D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; D008565:Membrane Proteins; C498710:PAG1 protein, human