Distinct CD30 Expression Patterns In Germinal Center B-Cell (GCB) and Non-GCB Diffuse Large B-Cell Lymphoma (DLBCL)

Background DLBCL is the most common type of non-Hodgkin lymphoma, which demonstrates morphologic, immunophenotypic, molecular, and clinical heterogeneity. Gene expression profiling studies define two molecular subtypes of DLBCL, namely germinal center B-cell-like (GCB) and activated B-cell-like (ABC) DLBCL. Hans' algorithm was developed to provide an immunohistochemical correlation to the molecular subtypes of DLBCL. In the pre and post-rituximab era, ABC subtype of DLBCL is known to demonstrate poor overall survival when compared to GCB subtype. In addition, relapsed or primary refractory DLBCL responds poorly to current therapeutic strategies. These findings underscore the necessity to identify novel therapeutic targets in DLBCL to achieve better clinical outcomes. Recent data suggests that CD30, a member of the tumor necrosis factor receptor family, is a potential therapeutic target in DLBCL. CD30 is widely expressed in classical Hodgkin lymphoma (cHL) and anaplastic large cell lymphoma (ALCL) thus serving as an attractive target of immunotherapy for cHL and ALCL. In this study we conducted a retrospective evaluation of CD30 expression in GCB and non-GCB DLBCL, treated at our Institution with standard front-line chemo-immunotherapy (i.e. R+CHOP or R+ DA-EPOCH). Materials and Methods We identified 60 patients with confirmed DLBCL for which archived formalin fixed paraffin embedded tissue was available in the form of a tissue micro-array (39 Cases) or diagnostic biopsy material (21 Cases). Immunohistochemical detection of CD30 was performed using routine methods (Biocare #PM031, ready to use aliquots). Demographic, clinical and pharmacological parameters were obtained for each patient. DLBCL cases were subtyped as GCB or non-GCB using immunohistochemistry-based Hans' algorithm. Membranous and Golgi pattern of CD30 expression in the tumor cells was designated as positive. Results 21 patients (48.8%) were classified as GCB, 22 patients (51.2%) non-GCB. CD30 expression was detected in 13.3% of all DLBCL patients. Differences in CD30 expression were noted between GCB- and non-GCB DLBCL. CD30 expression was detected in 9.5% and 23% of the GCB- and non-GCB DLBCL subtypes respectively. Demographics and clinical characteristics were equally distributed between GCB- and non-GCB and between CD30 positive or negative DLBCL. Patients received either R+CHOP (82%) or R+DA-EPOCH (18%). The complete response (CR) rate of the entire cohort was 67% and no differences were observed between GCB- or non-GCB DLBCL. CD30 (+) DLBCL had a higher CR (complete response) rate than CD30 (-) DLBCL (88% vs 63.4%). However, the numbers were too small to reach statistical significance. No significant differences were observed between CD30 (+) or (-) DLBCL in terms of progression free survival (PFS) (CD30[-]37m vs. CD30[+]16.5m, P =0.785) or overall survival (OS) (CD30[-]86m vs. CD30[+]57.4m, P =0.99). In contrast to previously reported by other investigators, there was no difference in the clinical outcome between GCB vs. non-GCB DLBCL treated with R+CHOP or R+DA-EPOCH. Conclusions Our data suggests that CD30 expression is more prevalent in non-GCB DLBCL patients based on our small cohort. While CD30 expression may not confer a prognostic value in newly diagnosed DLBCL ([Table 1][1]), routine testing for it may identify a group of patients that may benefit from CD30-targeted therapeutic strategies (i.e. antibody-drug conjugates) in the relapsed/refractory setting. (Research, in part, supported by The Eugene and Connie Corasanti Lymphoma Research Fund) View this table: Table 1 Differences in clinical outcomes between GCB or non-GCB-DLBCL by CD30 status Disclosures: Czuczman: Genetech, Onyx, Celgene, Astellas, Millennium, Mundipharma: Advisory Committees Other. Hernandez-Ilizaliturri: Seattle Genetics: Consultancy, Honoraria. [1]: #T1