Recent advances in CD5 diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL), the most common non-Hodgkin's lymphoma (NHL), is substantially heterogeneous. Approximately 5-10% of DLBCLs express CD5, which makes CD5 DLBCL a rare subgroup. Different studies have shown that CD5 DLBCL patients are often older and female and have higher lactate dehydrogenase levels, an Eastern Cooperative Oncology Group (ECOG) performance status > 1, and higher International Prognostic Index (IPI) scores. Moreover, patients often have advanced stage disease with a high incidence of central nervous system (CNS) relapse and bone marrow involvement. CD5 DLBCL cells are more likely to express MYC, BCL-2, and MUM-1, less likely to express CD10, and most belong to the activated B-cell-like (ABC) subtype. The potential mechanisms underlying the poor prognosis of CD5 DLBCL patients may be related to CD5-mediated B-cell receptor (BCR)-dependent and -independent pathways. The efficacy of the traditional rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) regimen is unsatisfactory in CD5 DLBCL patients. Despite supporting evidence from retrospective studies, it is currently unclear whether dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin plus rituximab (DA-EPOCH-R) can improve outcomes in this population. Several new drugs, such as Bruton tyrosine kinase inhibitors (BTKi), BCL-2 inhibitors, and CXCR4 antagonists, as well as immunotherapy, may help to improve the prognosis of CD5 DLBCL patients, but additional clinical explorations are needed to determine the optimal therapeutic strategy for this disease.