Survival after treatment of diffuse large-B-cell lymphoma is influenced by differences in immune cells, fibrosis, and angiogenesis in the tumor microenvironment.

Gene-expression profiling is an accurate, quantitative method for distinguishing Burkitt's lymphoma from diffuse large-B-cell lymphoma.

Key Points A 20-gene gene expression-based assay accurately and robustly assigns COO subtypes of DLBCL using formalin-fixed paraffin-embedded tissue.

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

A B S T R A C T PurposePatients with diffuse large B-cell lymphoma (DLBCL) can be divided into prognostic groups based on the cell of origin of the tumor as determined by microarray analysis. Various immunohistochemical algorithms have been developed to replicate these microarray results and/or stratify patients according to survival. This study compares some of those algorithms and also proposes some modifications. Patients and MethodsTwo-hundred and sixty-two cases of de novo DLBCL treated with rituximab and cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or CHOP-like therapy were examined. ResultsThe Choi algorithm and Hans algorithm had high concordance with the microarray results. Modifications of the Choi and Hans algorithms for ease of use still retained high concordance with the microarray results. Although the Nyman and Muris algorithms had high concordance with the microarray results, each had a low value for either sensitivity or specificity. The use of LMO2 alone showed the lowest concordance with the microarray results. A new algorithm (Tally) using a combination of antibodies, but without regard to the order of examination, showed the greatest concordance with microarray results. All of the algorithms divided patients into groups with significantly different overall and event-free survivals, but with different hazard ratios. With the exception of the Nyman algorithm, this survival prediction was independent of the International Prognostic Index. Although the Muris algorithm had prognostic significance, it misclassified a large number of cases with activated B-cell type DLBCL. ConclusionThe Tally algorithm showed the best concordance with the microarray data while maintaining prognostic significance and ease of use.

BackgroundCyclin D1-negative mantle cell lymphoma is difficult to distinguish from other small B-cell lymphomas. The clinical and pathological characteristics of patients with this form of lymphoma have not been well defined. Overexpression of the transcription factor SOX11 has been observed in conventional mantle cell lymphoma. The aim of this study was to determine whether this gene is expressed in cyclin D1-negative mantle cell lymphoma and whether its detection may be useful to identify these tumors.

SUMMARY We investigated the transcriptional and epigenetic repression of miR-29 by Myc, HDAC3, and EZH2 in mantle cell lymphoma and other Myc-associated lymphomas. We demonstrate that miR-29 is repressed by Myc through a co-repressor complex with HDAC3 and EZH2. Myc contributes to EZH2 upregulation via repression of the EZH2 targeting miR-26a, and EZH2 induces Myc via inhibition of the Myc targeting miR-494 to create positive feedback. Combined inhibition of HDAC3 and EZH2 cooperatively disrupted the Myc-EZH2-miR-29 axis, resulting in restoration of miR-29 expression, down-regulation of miR-29 targeted genes, and lymphoma growth suppression in vitro and in vivo. These findings define a Myc-mediated miRNA repression mechanism, shed light on Myc lymphomagenesis mechanisms and reveals promising therapeutic targets for aggressive B-cell malignancies.

Lymphomas arising from NK or gd-T cells are very aggressive diseases and little is known regarding their pathogenesis. Here we report frequent activating mutations of STAT3 and STAT5B in NK/T-cell lymphomas (n ¼ 51), gd-T-cell lymphomas (n ¼ 43) and their cell lines (n ¼ 9) through next generation and/or Sanger sequencing. STAT5B N642H is particularly frequent in all forms of gd-T-cell lymphomas. STAT3 and STAT5B mutations are associated with increased phosphorylated protein and a growth advantage to transduced cell lines or normal NK cells. Growth-promoting activity of the mutants can be partially inhibited by a JAK1/2 inhibitor. Molecular modelling and surface plasmon resonance measurements of the N642H mutant indicate a marked increase in binding affinity of the phosphotyrosine-Y699 with the mutant histidine. This is associated with the prolonged persistence of the mutant phosphoSTAT5B and marked increase of binding to target sites. Our findings suggest that JAK-STAT pathway inhibition may represent a therapeutic strategy.