non-GCB Subtype Research Articles

Immunohistochemical Expression Pattern of Germinal Center and Non-Germinal Center Markers Correlates with Prognosis in Diffuse Large B-Cell Lymphoma.

Recent studies have shown correlations between diffuse large B-cell lymphoma (DLCBL) prognosis and molecular features using genome profiles by cDNA microarrays. Since this analysis is not routinely used, immunohistochemical tests for prediction of DLBCL survival are gaining major importance, using markers as, CD10, BCL-6 and MUM-1 to identify germinal center B-cell (GCB) and non-GCB, respectively. The goal of this study was to evaluate the significant effect on survival within GCB and non-GCB subgroup.Patients and Methods: Seventy-four untreated pts (median age: 58 yrs: 38M/36F) with DLBCL de novo diagnosed in a single institution, treated with CHOP-like regimens. Tissue microarrays (TMA) blocks were created from paraffin-embedded, formalin-fixed block and stained with antibodies to CD20 (clone L26, Dako), CD10 (clone 56C6; Novocastra; NCL-CD10-270), BCL-6 (clone GI 191E/A8; Cell Mark; CMC 798) and MUM1 (clone MUM1p; Dako, CA; M7259). Results. Cases were subclassified using CD10, BCL-6, and MUM1 expression, and 25 cases (33.8%) were considered GCB and 49 cases (66.2%) non-GCB. The 2-year overall survival (OS) for the GCB group was 80% compared with only 38.9% for the non-GCB (p<0.001). In the multivariate analysis, only the International Prognostic Index score (IPI 3-4 HR=2.6, p=0.013) and the GCB phenotype (Non-GCB HR=2.7, p=0.054) were independent prognostic factors. In summary, immunohistochemical expression of CD10, BCL-6 and MUM1 are able to determine the GCB and non-GCB subtypes of DLBCL and predict survival.

Confirmation of the molecular classification of diffuse large B-cell lymphoma by immunohistochemistry using a tissue microarray

AbstractDiffuse large B-cell lymphoma (DLBCL) can be divided into prognostically important subgroups with germinal center B-cell–like (GCB), activated B-cell–like (ABC), and type 3 gene expression profiles using a cDNA microarray. Tissue microarray (TMA) blocks were created from 152 cases of DLBCL, 142 of which had been successfully evaluated by cDNA microarray (75 GCB, 41 ABC, and 26 type 3). Sections were stained with antibodies to CD10, bcl-6, MUM1, FOXP1, cyclin D2, and bcl-2. Expression of bcl-6 (P < .001) or CD10 (P = .019) was associated with better overall survival (OS), whereas expression of MUM1 (P = .009) or cyclin D2 (P < .001) was associated with worse OS. Cases were subclassified using CD10, bcl-6, and MUM1 expression, and 64 cases (42%) were considered GCB and 88 cases (58%) non-GCB. The 5-year OS for the GCB group was 76% compared with only 34% for the non-GCB group (P < .001), which is similar to that reported using the cDNA microarray. Bcl-2 and cyclin D2 were adverse predictors in the non-GCB group. In multivariate analysis, a high International Prognostic Index score (3-5) and the non-GCB phenotype were independent adverse predictors (P < .0001). In summary, immunostains can be used to determine the GCB and non-GCB subtypes of DLBCL and predict survival similar to the cDNA microarray.