Clinicopathologic Evaluation of Subgroups of Diffuse Large B Cell Lymphoma by Immunohistochemistry

Diffuse large B cell lymphoma (DLBCL) has become an emerging epidemic in recent years. Striking heterogeneity in its clinical, biological and treatment responses prompted us to identify variation in our study group. The aim was to classify the DLBCL into prognosis-based subgroups according to the WHO classification and to evaluate their relation to clinical parameters (age, gender, anatomic location and B symptoms), as well as bcl 2 and Ki 67 status. Patients and
Methods: A cross sectional study was carried out on 42 DLBCL patients, classified histologically and immunophenotypically into germinal center B cell like (GCB) or non-GCB type. Immunohistochemistry (IHC) was performed using antibodies against CD 10, MUM-1 and bcl 6; additionally anti-apoptotic protein bcl 2 and proliferative marker Ki 67 (using cutoff value of 70%) were also assayed by IHC.
Results: Of the total 27/42 (64%) were males and 15/42 (36%) females, with a mean age of 44.1±15 years. 15/42 (36%) cases were of GCB type as compared to 27/42 (64%) of non GCB type. Extranodal involvement and B symptoms were seen in 18/27 (66.6%) and 20/27(74%) of the non GCB type, whereas bcl 2 protein expression and Ki 67 proliferative index (PI) <70% were each noted in 22/27 (81.4%).
Conclusion: We document an astonishingly high number of non-GCB type DLBCL in our population. It is alarming to see such an aggressive tumor proliferating in our region. Significant association of non-GCB type with extranodal origin, B symptoms and low Ki 67 PI (<70%) is another concern.