Diffuse large B-cell lymphoma (DLBCL) can be divided into prognostically important subgroups with germinal center Bcell-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. IntroductionDiffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma and accounts for 30% to 40% of new diagnoses. 1,2 However, DLBCL is heterogeneous both clinically and morphologically. Despite the use of anthracycline-based chemotherapy, durable remissions are achieved in only 40% to 50% of patients. 2 Therefore, it is important to identify at diagnosis those patients who may benefit from more aggressive or experimental therapies.Currently, the prognosis of patients with DLBCL is estimated using the clinical parameters of the International Prognostic Index (IPI). 3 However, these clinical parameters reflect a mixture of underlying biologic or genetic differences. In an attempt to elucidate these underlying factors, the prognostic value of numerous individual proteins has been studied by immunoperoxidase and molecular techniques. However, these studies have yielded conflicting results, and none have been validated in a large prospective trial. Therefore, in contrast to the IPI, these individual markers are generally not used in clinical practice for selecting therapy or predicting prognosis.Using a cDNA microarray, DLBCL can be divided into prognostically significant subgroups with germinal center B-celllike (GCB), activated B-cell-like (ABC), or type 3 gene expression profiles. 35,36 The GCB group has a significantly better survival than the ABC group. The type 3 group is heterogeneous and not well defined, but has a poor outcome similar to the ABC group. Another study using an oligonucleotide array has demonstrated that DLBCL can be divided into 2 molecularly distinct populations (cured and fatal/refractory). 37 Because this technology is expensive and not generally available, a sim...

Purpose: Hans and coworkers previously developed an immunohistochemical algorithm with ∼80% concordance with the gene expression profiling (GEP) classification of diffuse large B-cell lymphoma (DLBCL) into the germinal center B-cell-like (GCB) and activated B-cell-like (ABC) subtypes. Since then, new antibodies specific to germinal center B-cells have been developed, which might improve the performance of an immunostain algorithm. Experimental Design: We studied 84 cases of cyclophosphamide-doxorubicin-vincristineprednisone (CHOP)-treated DLBCL (47 GCB, 37 ABC) with GCET1, CD10, BCL6, MUM1, FOXP1, BCL2, MTA3, and cyclin D2 immunostains, and compared different combinations of the immunostaining results with the GEP classification. A perturbation analysis was also applied to eliminate the possible effects of interobserver or intraobserver variations. A separate set of 63 DLBCL cases treated with rituximab plus CHOP (37 GCB, 26 ABC) was used to validate the new algorithm. Results: A new algorithm using GCET1, CD10, BCL6, MUM1, and FOXP1 was derived that closely approximated the GEP classification with 93% concordance. Perturbation analysis indicated that the algorithm was robust within the range of observer variance. The new algorithm predicted 3-year overall survival of the validation set [GCB (87%) versus ABC (44%); P < 0.001], simulating the predictive power of the GEP classification. For a group of seven primary mediastinal large B-cell lymphoma, the new algorithm is a better prognostic classifier (all "GCB") than the Hans' algorithm (two GCB, five non-GCB). Conclusion: Our new algorithm is significantly more accurate than the Hans' algorithm and will facilitate risk stratification of DLBCL patients and future DLBCL research using archival materials. (Clin Cancer Res 2009;15(17):5494-502) Gene expression profiling (GEP) studies have shown that diffuse large B-cell lymphoma (DLBCL) can be reproducibly divided into the prognostically important subtypes of germinal center B-cell-like (GCB), activated B-cell-like (ABC), and unclassified DLBCL (1-3). When treated with a regimen containing cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or other CHOP-like regimens (CHOPtreated), patients with GCB-DLBCL have a better survival

In this retrospective study, we have shown that the subclassification of DLBCL on the basis of the cell of origin continues to have prognostic importance in the rituximab era.

Treating all DLBCL as a single entity ignores the mechanistic differences in BCL2 upregulation and obscures the prognostic significance of BCL2 expression. Hence, the significance of BCL2 and other biomarkers should be assessed in the context of DLBCL subgroups in future studies.

Gene expression profiling of diffuse large B-cell lymphoma (DLBCL) has revealed prognostically important subgroups: germinal center B-cell-like (GCB) DL-BCL, activated B cell-like (ABC) DLBCL, and primary mediastinal large B-cell lymphoma. The t(14;18)(q32; q21) has been reported previously to define a unique subset within the GCB-DLBCL. We evaluated for the translocation in 141 cases of DLBCL that were successfully gene expression profiled. Using a dual-probe fluorescence in situ hybridization assay, we detected the t(14;18) in 17% of DLBCLs and in 34% of the GCB subgroup which contained the vast majority of positive cases. In addition, 12 t(14;18)-positive cases detected by polymerase chain reaction assays on additional samples were added to the fluorescence in situ hybridization-positive cases for subsequent analysis. Immunohistochemical data indicated that BCL2, BCL6, and CD10 protein were preferentially expressed in the t(14;18)-positive cases as compared to t(14;18)-negative cases. Within the GCB subgroup, the expression of BCL2 and CD10, but not BCL6, differed significantly between cases with or without the t(14; 18): 88% versus 24% for BCL2 and 72% versus 32% for CD10, respectively. In the GCB-DLBCL subgroup, a heterogeneous group of genes is overexpressed in the t(14;18)-positive subset, among which BCL2 is a significant discriminator. Interestingly, the t(14;18)-negative subset is dominated by overexpression of cell cycle-associated genes, indicating that these tumors are significantly more proliferative, suggesting distinctive pathogenetic mechanisms. However, despite this higher proliferative activity, there was no significant difference in overall or failure-free survival between the t(14;18)-positive and -negative subsets within the GCB subgroup. Diffuse large B-cell lymphoma (DLBCL) is an aggressive malignancy of mature B cells with an annual incidence of ϳ25,000 cases in the United States. DLBCL is a heterogeneous entity both clinically and morphologically. We have recently shown by gene expression profiling that DLBCL can be classified into two major subgroups. 1 The germinal center B-cell-like (GCB) subgroup expresses genes characteristic of normal GC B cells and is associated with a good outcome after multiagent chemotherapy, whereas the activated B-cell-like (ABC) subgroup expresses genes characteristic of activated blood B cells and is associated with a poor clinical outcome. Nonetheless, considerable molecular heterogeneity exists within each subgroup. A small number of DLBCL cases are unclassifiable and do not express the GCB or ABC sig-

We conclude that LMO2 protein expression is a prognostic marker in DLBCL patients treated with anthracycline-based regimens alone or in combination with rituximab. After further validation, immunohistologic analysis of LMO2 protein expression may become a practical assay for newly diagnosed DLBCL patients to optimize their clinical management.

Gene expression profiling of diffuse large B-cell lymphoma (DLBCL) has revealed biologically and prognostically distinct subgroups: germinal center B-cell-like (GCB), activated B-celllike (ABC) and primary mediastinal (PM) DLBCL. The BCL6 gene is often translocated and/or mutated in DLBCL. Therefore, we examined the BCL6 molecular alterations in these DLBCL subgroups, and their impact on BCL6 expression and BCL6 target gene repression. BCL6 translocations at the major breakpoint region (MBR) were detected in 25 (18.8%) of 133 DLBCL cases, with a higher frequency in the PM (33%) and ABC (24%) subgroups than in the GCB (10%) subgroup. Translocations at the alternative breakpoint region (ABR) were detected in five (6.4%) of 78 DLBCL cases, with three cases in ABC and one case each in the GCB and the unclassifiable subgroups. The translocated cases involved IgH and non-IgH partners in about equal frequency and were not associated with different levels of BCL6 mRNA and protein expression. BCL6 mutations were detected in 61% of DLBCL cases, with a significantly higher frequency in the GCB and PM subgroups (470%) than in the ABC subgroup (44%). Exon-1 mutations were mostly observed in the GCB subgroup. The repression of known BCL6 target genes correlated with the level of BCL6 mRNA and protein expression in GCB and ABC subgroups but not with BCL6 translocation and intronic mutations. No clear inverse correlation between BCL6 expression and p53 expression was observed. Patients with higher BCL6 mRNA or protein expression had a significantly better overall survival. The biological role of BCL6 in translocated cases where repression of known target genes is not demonstrated is intriguing and warrants further investigation.

We sought to determine whether identification of poor-risk subgroups of diffuse large B-cell lymphoma (DLBCL) using immunohistochemical stains would have practical utility with regard to prognosis and therapeutic decisions. Tissue microarray blocks were created using replicate samples of formalin-fixed, paraffin-embedded tissue from 200 cases of de novo DLBCL. The sections were stained with antibodies to proteins that are expressed by activated or proliferating B cells including MUM1, FOXP1, bcl-2, survivin, protein kinase C-beta (PKC-b), cyclin D2, cyclin D3, and Ki-67. In univariate analysis, tumor expression of cyclin D2 (P ¼ 0.025) or PKC-b (P ¼ 0.015) was associated with a worse overall survival, whereas none of the other markers was predictive of overall survival. Patients with DLBCL that expressed either cyclin D2 or PKC-b had a 5-year overall survival of only 30% as compared to 52% for those who were negative for both markers (P ¼ 0.0019). In multivariate analysis, the expression of cyclin D2 or PKC-b was an independent predictor of poor overall survival (P ¼ 0.035). Cyclin D2 and PKC-b expression will be useful in designing a 'biological prognostic index' for patients with DLBCL.