Coexpression of MYC and BCL2 oncoproteins in primary nodal versus primary extranodal diffuse large B-cell lymphoma

Objectives: Diffuse large B-cell lymphoma (DLBCL) is a morphologically and molecularly diversified disease with aggressive biological behavior. The double expression of MYC/BCL2 proteins portends a poorer prognosis. This study aims to evaluate the frequency, describe the clinicopathological features of the double-expressor phenotype of DLBCL in primary nodal (PN) versus primary extranodal (PEN) sites, and investigate their associations. Materials and Methods: A total of 48 patients with the double-expressor phenotype of lymphoma (DEPL) in a tertiary care hospital were included over three years. Clinicopathological parameters and associations were investigated based on the primary site. Statistical Analysis: Data were documented and analyzed using appropriate statistical tests. Results: The incidence of DEPL in our study was 28.7%. The median age of all DEPL patients was 56 years, with a predominance of men (69%). DEPL cases were further subcategorized as PN-DEPL ( n = 33) and PEN-DEPL ( n =15). Males were affected almost equally in both groups. More PN-DEPL patients exhibited B symptoms (82%), elevated lactate dehydrogenase (LDH) levels (73%), III/IV stage disease (71%), and maximum revised international prognostic index (R-IPI) score (64%) compared to PEN-DEPL patients. On the other hand, bone marrow (BM) involvement (87%), activated B-cell-type phenotype (80%), pathologic stage I/II (67%), and Ki67 index >90% (93%) were more common in PEN-DEPL patients. Conclusions: Significant differences were observed between PN-DEPL and PEN-DEPL in terms of B symptoms, LDH levels, stage at presentation, BM involvement, pathological subtype, Ki67 index, and R-IPI score. This study provides an estimate of the burden of this aggressive entity and encourages further prognostic studies and therapeutic trials.