Prognostic significance of immunohistochemical classification of diffuse large B-cell lymphoma.

Aim: To evaluate the clinical significance of immunoperoxidase staining for CD10, bcl-6, mum-1 and bcl-2 to subdivide DLBCL into prognostic subgroups, we analysed 50 DLBCL cases using immunohistochemical methods.
Methods and Results: Fifty DLBCL patients were evaluated retrospectively. The expression of CD10 was associated with better OS (p=0.04) whereas expression of mum-1 was associated with worse OS (p=0.009). There were no significance of OS in case of expression of bcl-6 (p=0.05) and bcl-2 (p=0.3). They were subclassified using CD10, mum-1, bcl-6 as germinal center B-cell like (GCB) lymphoma (30%) and non-GCB lymphoma (70%). The OS and EFS (event free survival) were longer in GCB group (p=0.002) and 5-year OS for GCB group was 92% compared with only 44% for the non-GCB group (p=0.02). The OS of the GCB group also was longer compared to that of the non-GCB group in low IPI subgroup (p=0.01).
Conclusion: The existence of survival differences between GCB a non-GCB group also in the patients with low IPI score, showed the importance of prognostic classification in the risk-adaptive treatment approaches. The classification as GCB and non-GCB based immunostains may enable to define more accurate prognostic groups in DLBCL.