NCCN Guidelines for Patients® | Diffuse Large B-cell Lymphoma

12 NCCN Guidelines for Patients ® : Diffuse Large B-cell Lymphoma, 2017 1 DLBCL basics Diagnosis The way cancer cells look may help to identify which type of cancer it is. DLBCL gets its name from the way it looks. The cancer cells are large and grow throughout tissue rather than in clusters. Protein tests For diagnosis, the hematopathologist needs to study the proteins in the cells’ surface (membrane). This is called immunophenotyping. DLBCL has a common pattern or “signature” of proteins. See Figure 4. These proteins are also studied to learn if the cancer is a GCB (germinal center B-cell) or non-GCB subtype. IHC panel An IHC ( i mmuno h isto c hemistry) panel is a test for these proteins. It involves applying a chemical marker to cells and then looking at them with a microscope. The IHC panel should test for BCL2, BCL6, CD3, CD5, CD10, CD20, CD45, IRF4/MUM1, Ki-67, and MYC. DLBCL cells often have CD20 and CD45 and no CD3. In some cases, it is helpful to learn the lymphoma subtype. To do so, the panel should also include ALK, CD30, CD138, cyclin D1, EBER-ISH, HHV8, SOX11, and kappa and lambda light chain proteins. Light chain proteins are part of antibodies. Flow cytometry Flow cytometry is a newer method that can also be used to assess the surface proteins on lymphoma cells. This method involves first adding a marker—a light-sensitive dye—to cells. Then, your blood will be passed through a flow cytometry machine. The machine measures surface proteins on thousands of cells. Figure 4 CD20 protein DLBCLs have a common pattern of proteins in their membrane. This pattern includes the presence of CD20 and CD45 and no CD3. Immunophenotyping is the process of identifying the proteins in cells’ membranes. Derivative work of Rituximab Binding to CD20 on a B Cell Surface by NIAID available at commons. Rituxima_Binding_to_CD20_on_a_B_Cell_Surface_(6830897205).jpg under a Creative Commons Attribution 2.0 Generic license