Growing Importance of MYC/BCL2 Immunohistochemistry in Diffuse Large B-Cell Lymphomas

Prognostic Index (IPI), which was established to predict outcome of patients with aggressive lymphoma treated in the prerituximab era, has been confirmed to be a valid prognosticator for patients receiving rituximab, with the differences between the four risk groups (low, low-intermediate, high-intermediate, and high) being smaller, yet still significant in the rituximab era. 2 However, within each of these IPI risk groups, there are considerable differences in outcome, suggesting underlying biologic differences that are not encompassed by the clinical parameters lactate dehydrogenase, age, advanced stage, performance state, and two or more extralymphatic sites of involvement. By gene expression profiling (GEP), DLBCL can be stratified into biologically and prognostically relevant subtypes 3,4 based on cell-of-origin (COO) gene signatures, with the activated B-cell type being associated with an inferior outcome com