Clinicopathologic significance and therapeutic implication of de novo CD5+ diffuse large B-cell lymphoma

Background: Various subsets of diffuse large B-cell lymphoma(DLBCL) are distinguished based on molecular and immunohistochemical features. As we know, CD5 is a pan-T-cell surface marker and is seldom expressed in DLBCL. Large-scale studies of de novo CD5+ DLBCL are lacking in Chinese patients.

Method: A total of 139 patients with DLBCL (30 CD5+ DLBCL and 109 CD5- DLBCL) who were immunophenotyped and treated with chemotherapy were subjected to this analysis. There were 85 males and 54 females. Their age ranged from 17 to 84 years old, and the median age was 58 years old.

Results: In this study CD5+ DLBCL was associated with higher IPI scores (>2), bone marrow involvement, higher probability of >1 ECOG performance status, non-germinal center B-cell like(non-GCB), BCL2 overexpression, whereas seldom expressed CD10 or BCL6, and unconspicuous higher expression of Ki67. With standard chemotherapy, CD5+ DLBCL patients had significantly worse overall survival (OS, median, 29.5 months vs. not reached, P = 0.0004) and progression-free survival (PFS, median, 18.0 months vs. not reached, P = 0.0002) than CD5- DLBCL patients, which had independent prognostic significance of the International Prognostic Index (IPI), and subtype of the non-GCB DLBCL. For CD5+ DLBCL, the addition of rituximab to chemotherapy may not significantly improve the OS (median, 14 months vs. 29.5 months, P = 0.72) and PFS (median, 10 months vs. 12 months, P = 0.92).

Conclusion: CD5+ DLBCL patients have the distinctive clinical and biological features, they should be provided with clinic individualized treatment and important pathways with therapeutic implications should be underscored.