Molecular Classification and Treatment of Diffuse Large B-Cell Lymphoma and Primary Mediastinal B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) encompasses a group of aggressive B-cell non-Hodgkin lymphomas with striking genetic heterogeneity and variable clinical presentations. Among these is primary mediastinal B-cell lymphoma (PMBL), which has unique clinical and molecular features resembling Hodgkin lymphoma. Treatment of DLBCL is usually curative, but identifiable subsets at highest risk for treatment failure may benefit from intensified chemotherapy regimens and/or targeted agents added to frontline therapy. Recent comprehensive genomic analyses have identified distinct genetic subtypes of DLBCL with characteristic genetic drivers and signaling pathways that are targetable. Immune therapy with chimeric antigen receptor T cells and checkpoint inhibitors has revolutionized the treatment of relapsed or refractory disease, and antibody drug conjugates have weaponized otherwise intolerable cytotoxic agents. Ongoing clinical trials are further refining the specificity of these approaches in different genetic subtypes and moving them from the setting of recurrent disease to frontline treatment in high-risk patient populations.