Basic immunohistochemistry for lymphoma diagnosis

Abstract

Immunohistochemistry is a technique that uses antigen-antibody interactions to detect specific proteins in cells. This technique has several essential applications in lymphoma diagnosis, including identifying the cell lineage and phase of maturation, detecting specific genetic alterations, visualizing the degree of cell proliferation, and identifying therapeutic targets. CD3 is a pan T-cell marker expressed on most of the mature T/NK-cell lymphomas, except for anaplastic large cell lymphoma, whereas CD20 is a pan B-cell marker that is expressed on most of the mature B-cell lymphomas. CD79a may be a good alternative to CD20, compensating for its loss owing to the plasmocytic differentiation of tumor cells or history of rituximab administration. CD56, a neuroendocrine marker, is used as an NK cell marker in lymphoma diagnosis. Characteristic translocations occurring in follicular lymphoma (BCL2) and mantle cell lymphoma (CCND1) can be detected by the overexpression of Bcl-2 and cyclin D-1 in immunohistochemistry, respectively. Ki-67 reflects the degree of tumor cell proliferation by indicating cells in cell cycle phases other than G0. With the development of immunotherapy, several antibodies against markers such as programmed death-ligand 1 (PD-L1), CD19, and CD30 have been used as biomarkers to identify therapeutic targets. It is critical to properly fix the specimens to obtain accurate immunohistochemical results. Therefore, all processes, from tissue collection to the final pathological diagnosis, must be performed appropriately for accurate lymphoma diagnosis.

Keywords: Immunohistochemistry; In situ hybridization; Lymphoma.

Fig. 1

Representative immuno-histochemical staining images of various type of diffuse large B-cell lymphomas. Abbreviations: ABC, activated B-cell type; DLBCL, diffuse large B-cell lymphoma; GCB, germinal center B-cell type; EBV DLBCL, EBV-positive diffuse large B-cell lymphoma.

Fig. 2

Representative images of immunohistochemical staining of small/low grade B-cell lymphomas. Tumor cells are positive for CD10 and Bcl-2 in follicular lymphoma, positive for CD5 and CD23 in chronic lymphocytic leukemia/small lymphocytic lymphoma, positive for cyclin D-1 and SOX11 in mantle cell lymphoma. Abbreviation: CLL/SLL, chronic lymphocytic leukemia/small lymphocytic lymphoma.

Fig. 3

Representative images of immunohistochemical staining of T/NK-cell lymphomas. In ALK-positive anaplastic large cell lymphoma, tumor cells are negative for CD3, and positive for CD30 and ALK. In angioimmunoblastic T-cell lymphoma, CD3 and CD20 shows mixed pattern of T- and B-cells. CD21 stain shows expanded follicular dendritic cell meshwork. EBV ISH is positive in scattered large B-cells. In extranodal NK/T-cell lymphoma, EBV positive cells are positive for CD3 and negative for CD79a in double stains. Abbreviations: AITL, angioimmuno-blastic T-cell lymphoma; ALCL, ana-plastic large cell lymphoma; ENKTL, extranodal NK/T-cell lymphoma.

Fig. 4

Representative images of immunohistochemical staining of precursor lymphomas. In T-lympho-blastic leukemia/lymphoma, tumor cells are positive for CD3, CD99 and TdT. In B-lymphoblastic leukemia/ lymphoma, tumor cells are negative for CD20, positive for CD79a and TdT.

Fig. 5

Representative immunohistochemical staining images of Hodgkin lymphomas. In classic Hodgkin lymphoma, tumor cells are positive for CD30 and CD15. CD20 is negative and PAX5 is weak positive in large tumor cells. In nodular lymphocyte predominant Hodgkin lymphoma, tumor cells are positive for CD20 and Oct-2. CD30 is negative in tumor cells. CD3 stain shows peritumoral rosette-like T-cells. Abbreviation: NLPHL, nodular lymphocyte predominant Hodgkin lymphoma.