[1454] BCL-6 Expression and Hans' Algorithm Are Able To Predict Patients' Outcome in Extranodal Diffuse Large B-Cell Lymphomas

S Uccella, I Ricotti, S Freguia, R Invernizzi, I Proserpio, G Pinotti, C Capella. University of Insubria, Varese, Italy; Ospedale di Circolo-University of Insubria, Varese, Italy

Background: The prognostic value of the determination of the cell of origin using Hans' algorithm in DLBCL has been a matter of debate in the last five years. In addition, a few studies have suggested an emerging role for Bcl-6 expression as a positive predictor of survival in these lymphomas. We have already examined a series of primary nodal de novo DLBCLs, showing that Bcl-6 expression, and not germinal centre (GC) phenotype, was able to predict better outcome in DLBCL patients. Now we report the study of a series of primary extranodal DLBCLs.
Design: 81 DLBCLs primarily arising in an extranodal site were collected from our files (36 gastric, 7 intestinal, 13 cervico-cephalic, 3 of the bone, 3 of the testis, 2 of the breast, 6 of the CNS, 7 cutaneous and 4 of other sites). For all cases, histological specimens and clinical data were available. 25 patients (32%) were treated with immunochemoterapy including Rituximab. The immunohistochemical expression of CD10, Bcl-6 and MUM1 was determined to reproduce Hans' algorithm. Survival analysis was performed using Kaplan-Mayer method and Cox's model.
Results: As extranodal DLBCLs are a heterogeneous group, in which prognosis is also determined by the site of origin, we first analyzed survival on the base of primary site, and we found, as expected, that CNS lymphomas had the worst prognosis, cutaneous lymphomas had the best, and the remaining cases had an intermediate survival. At immunohistochemistry, we found 36 (44%) cases with GC and 45 (56%) cases with activated (ABC) phenotype, almost homogeneously distrubuted in different sites, except for CNS DLBCLs, which were all of the ABC type. 65 (81%) lymphomas were Bcl-6-positive. The survival analysis showed that the GBC phenotype and Bcl-6 expression were related to a better outcome in terms of overall survival and lymphoma-specific survival. These results were confirmed when CNS and cutaneous cases were excluded from the analysis.
Conclusions: The GC phenotype detrmined using Hans' algorithm, and the presence of expression of Bcl-6 are positive predictors of a good outcome in patients with extranodal DLBCL, independently of primary site.
Category: Hematopathology

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 183, Wednesday Morning


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