Correlations between BCL6 rearrangement and outcome in patients with diffuse large B-cell lymphoma treated with CHOP or R-CHOP

Background

BCL6 gene rearrangement is the most frequent chromosomal abnormality in diffuse large B-cell lymphoma, a malignancy characterized by genetic heterogeneity and wide variability in clinical outcome. The prognostic significance of BCL6 rearrangement has not been evaluated in the context of rituximab therapy for diffuse large B-cell lymphoma. We analyzed the effect of the BCL6 rearrangement on survival in patients with diffuse large B-cell lymphoma treated with CHOP and CHOP plus rituximab (R-CHOP).

Design and Methods

BCL6 rearrangement status was analyzed by fluorescence in situ hybridization with break-apart probes in 164 patients with diffuse large B-cell lymphoma treated with CHOP (n=65) or R-CHOP (n=99). Cell-of-origin immunophenotype including BCL6 protein expression were determined by immunohistochemistry on a tissue microarray.

Results

BCL6 rearrangement was detected in 19.5% of cases. The presence of the gene rearrangement was associated with a non-germinal center B-cell immunophenotype (P=0.006), and showed no correlation with BCL6 protein expression. A trend toward inferior overall survival was observed in association with the BCL6 rearrangement among patients treated with R-CHOP (P=0.08), but not among patients treated with CHOP (P=0.64). However, BCL6 rearrangement also correlated with a high International Prognostic Index score (P=0.02), and did not demonstrate independent prognostic value by multivariate analysis.

Conclusions

The introduction of rituximab may have altered the prognostic impact of BCL6 gene rearrangement in patients with diffuse large B-cell lymphoma. However, prospective analysis within large randomized clinical trials will be needed to clarify the prognostic significance of this biomarker in the rituximab era.     

BCL3 rearrangement, amplification and expression in diffuse large B-cell lymphoma

Aims: Aim of the study is to investigate diffuse large B‐cell lymphoma (DLBCL) for the presence of BCL3 gene rearrangement and protein expression and to correlate these with immunophenotypic subsets of DLBCL. We aimed to investigate the pathogenetic implication of BCL3 in DLBCL. Methods and results: Tissue microarray sections from 78 DLBCLs were evaluated for BCL3 protein expression using immunohistochemistry and for BCL3 and IGH rearrangement using Fluorescent in situ hybridisation (FISH) with split‐apart probes. BCL3 expression was positive in 36/78 cases, of which BCL3 rearrangement was seen seen in one case. Three additional cases showed evidence of trisomy of BCL3/chromosome 19, and two of these three cases showed BCL3 expression. The four cases with FISH‐detectable abnormalities showed MUM1 expression and had a non‐germinal center (GC) phenotype. The median [and inter‐quartile range (IQR)] percentage of BCL3‐positive cells in MUM1‐positive and MUM1‐negative subsets was 65% (5–85%) and 5% (0–20%), respectively (P < 0.001). The median (IQR) percentage of BCL3‐positive cells among GC and non‐GC subsets of DLBCLs was 12% (12–81%) and 60% (6–87%), respectively (P = 0.022). Conclusion: Rearrangement or amplification involving the BCL3 gene is a rare event in DLBCL but is likely to play a role in the pathogenesis of a minority of de novo DLBCL. BCL3 over‐expression is more frequent and occurs in the absence of rearrangement or amplification and is a feature of the non‐GC subset of DLBCL.     

Coexpression of MYC and BCL-2 predicts prognosis in primary gastrointestinal diffuse large B-cell lymphoma

AIM:To investigate whether MYC and BCL-2 coexpression has prognostic significance in primary gastrointestinal diffuse large B-cell lymphoma(PGI-DLBCL)patients,and explore its associations with patients’clinical parameters.METHODS:Fresh and paraffin-embedded tumor tissue samples from 60 PGI-DLBCL patients who had undergone surgery at the Tianjin Medical University Cancer Institute and Hospital from January 2005 to May 2010 were obtained,and 30 lymphoid tissue samples from reactive lymph nodes of age-and sexmatched patients represented control samples.Staging and diagnostic procedures were conducted according to the Lugano staging system.All patients had been treated with three therapeutic modalities:surgery,chemotherapy,or radiotherapy.Expression of MYC and BCL-2 were detected at both protein and m RNA levels by immunohistochemistry and real-time RT-PCR.RESULTS:Positive expression levels of MYC and BCL-2proteins were detected in 35%and 45%of patients,respectively.MYC+/BCL-2+protein was present in30%of patients.MYC and BCL-2 protein levels were correlated with high MYC and BCL-2 m RNA expression,respectively(both P0.05).We found that advancedstage disease(atⅡE-Ⅳ)was associated with MYC and BCL-2 coexpression levels(P0.05).In addition,MYC+/BCL-2+patients had more difficulty in achieving complete remission than others(P0.05).Presenceof MYC protein expression only affected overall survivaland progression-free survival(PFS)when BCL-2 proteinwas coexpressed.The adverse prognostic impact ofMYC+/BCL-2+protein on PFS remained significant(P0.05)even after adjusting for age,Lugano stage,international prognostic index,and BCL-2 proteinexpression in a multivariable model.CONCLUSION:MYC+/BCL-2+patients have worsechemotherapy response and poorer prognosis thanpatients who only express one of the two proteins,suggesting that assessment of MYC and BCL-2 expressionby immunohistochemistry has clinical significance inpredicting clinical outcomes of PGI-DLBCL patients.     

Tissue microarray is inappropriate for analysis of BCL6 expression in diffuse large B-cell lymphoma

OBJECTIVE: In this study, our aim was to investigate how different immunohistochemical techniques may influence the result of BCL6 positivity and categorization in germinal center (GC) and non-GC derived diffuse large B-cell lymphoma (DLBCL), as it has been proposed that classification of DLBCL according to cell-of-origin by immunohistochemistry may be performed as a routine procedure in the diagnostic work-up. However, a number of technical issues need to be solved before introducing this as a standard technique. METHODS: Tumor specimens from 122 patients with de novo stage II-IV disease, adequately treated with anthracycline-containing chemotherapy regimens were collected. Immunohistochemical expression of BCL6, CD10, and MUM-1/IRF4 was examined using a tissue microarray (TMA) technique. BCL6 and CD10 were also evaluated on whole tissue sections. RESULTS: Due to profound tissue heterogeneity, BCL6 showed a wide range of positivity, with a high number of false negative results by TMA (25% positive), compared to 53% on whole tissue sections (WTS). CD10 was more homogeneously expressed, and TMA results corresponded better to WTS. Consequently, the results from categorization into GC and non-GC DLBCL differed considerably by use of the two methods, and resulted in very different outcome in terms of overall survival. CONCLUSION: Immunohistochemical GC-status determined on TMA is not reliable enough to be used for individual treatment decisions in DLBCL, mostly due to difficulties in interpreting BCL6 status.     

Rearrangement of the BCL6 gene in B-cell lymphoid neoplasms: comparison with lymphomas associated with BCL2 rearrangement

We report a series of B-cell neoplasms with regard to rearrangement of the BCL6 gene on chromosome band 3q27. Southern blot analysis using probes from the major translocation cluster (MTC) region of the BCL6 revealed rearrangement in 21/197 patients (10.7%) with B-cell neoplasms studied at presentation, and 11/25 patients (44%) first studied at relapse. In non-Hodgkin's lymphoma (NHL) studied at diagnosis, rearrangements of the BCL6 gene were not closely associated with a specific histopathologic subtype but distributed in subcategories in the Working Formulation. The incidence in follicular lymphoma was 12.1%, with significantly higher frequency in mixed and large cell subtypes, and that in diffuse aggressive lymphoma was 14.1%. Comigration analysis using probes from the immunoglobulin genes revealed association of the BCL6 gene with one of the three immunoglobulin loci in 9/25 cases analysed. A comparative study between NHL associated either with BCL2 or BCL6 rearrangement showed that advanced disease and bone marrow involvement were more frequent in BCL2(+) NHL. In contrast, extranodal involvement was more frequently observed in the BCL6(+) NHL. The survival curve of BCL6(+) NHL was characterized by a rapid decline followed by a plateau. Of the total of 32 BCL6(+) patients, six carried both BCL2 and BCL6 rearrangements; five of these six showed clinicopathological properties characteristic of follicular lymphoma, suggesting that the presence of the two genetic abnormalities does not necessarily have synergistic effects on malignant phenotypes. The high level of BCL6 expression in follicular lymphoma cell lines carrying a BCL2 rearrangement suggests that the deregulated BCL2 gene may have an effect on the development of genetic abnormalities of the BCL6 gene. The present study suggests that BCL6 gene rearrangement is primarily involved in large cell lymphoma irrespective of growth pattern of neoplastic cells, and that BCL6(+)BCL2(?) NHL could be curable with modern intensive chemotherapy.     

Analysis of internal deletions within the BCL6 gene in B-cell non-Hodgkin's lymphoma

The BCL6 gene is frequently altered by chromosomal translocations and/or point mutations at its 5' non-coding portion in B-cell non-Hodgkin's lymphoma (B-NHL). We analysed submicroscopic structural alterations of the BCL6 gene which had arisen from internal deletion in four cases with B-NHL and found that these deletions overlapped at the 280 bp region in the first intron. In electrophoretic mobility shift assay, nuclear extracts prepared from various cell lines were shown to bind to a fragment from this commonly deleted region. Our results suggest that deregulation of BCL6 expression would be caused by loss of this putative protein-binding sequence in some B-NHL cases.     

BCL6 rearrangement in a patient with mantle cell lymphoma

 We describe a patient with mantle cell lymphoma (MCL) associated with BCL6 gene rearrangement. MCL is a distinct subtype of non-Hodgkin's lymphoma characterized by CD5+, CD10–, CD20+, t(11;14)(q13;q32) and PRAD1/cyclin D1 overexpression. Although rearrangement of the BCL6 gene is the most frequent genetic change among diffuse lymphomas and some follicular lymphomas this is the first report of a patient with MCL associated with BCL6 rearrangement. Received: 6 January 1997 / Accepted: 17 February 1997     

Primary cutaneous diffuse large B-cell lymphoma (leg type) after renal allograft: case report and review of the literature

We report a case of a 58-year-old man who presented with a rapidly growing proliferative lesion on the left lower limb, clinically resembling a soft tissue sarcoma 3 years after renal allograft. There was no evidence of systemic involvement on bone marrow needle aspiration and computed tomography (CT) scans of the chest and abdomen. The lesion turned out to be primary cutaneous diffuse large B-cell lymphoma, leg type (PCLBCL LT), as defined in the recent World Health Organization–European Organization for Research and Treatment of Cancer (WHO–EORTC) classification of cutaneous lymphomas by skin biopsy. Immunosuppression reduction, chemotherapy with CHOP regimen and local radiotherapy induced complete remission of the tumor.     

MYC translocation partner gene determines survival of patients with large B‐cell lymphoma with MYC‐ or double‐hit MYC/BCL2 translocations

In large B‐cell lymphoma (LBCL) MYC‐ and MYC/BCL2 double‐hit (DH) translocations have been associated with inferior survival. We hypothesised that the negative prognostic impact of MYC translocation was determined by an immunoglobulin MYC translocation partner gene (IG‐MYC), as opposed to a non‐immunoglobulin partner gene (nonIG‐MYC). In a prospective, unselected cohort of 237 LBCL patients MYC and BCL2 translocations were identified by Flourescent in situ hybridisation (FISH) with split probes. MYC translocation partner gene was identified by IGH/MYC fusion probes and/or kappa/lambda split probes. Clinical data were collected from patient files. MYC translocation was identified in 28/225 patients. IG‐MYC translocation partner gene was identified in 12/24 patients. DH translocation was identified in 23/228 patients. IG‐MYC translocation partner gene was identified in 9/19 DH patients. Neither MYC‐nor DH translocation showed correlation with survival. However, MYC translocation with IG‐MYC translocation partner gene was associated with worse OS compared with both MYC translocation with nonIG‐MYC translocation partner gene (P = 0.02) as well as absence of MYC translocation (P = 0.03). In patients with DH a similar, however, stronger correlation was seen (P = 0.003 and P = 0.0004 respectively). MYC – or DH translocation with nonIG‐MYC translocation partner gene was not associated with worse overall survival (P = 0.2 and P = 0.3 respectively). Most patients received Rituximab (86%) and CHOP/CHOP‐like chemotherapy regimes (81%). We suggest that prognostic stratification of LBCL patients by MYC and/or DH translocations should include identification of MYC translocation partner gene because approximately half of the cases harbour nonIG‐MYC translocation partner genes with no or minor influence on survival.     

Primary cutaneous diffuse large B‐cell lymphoma,leg type,with features simulating POEMS syndrome

A 91‐year‐old woman presented with a rapidly proliferative cutaneous lesion on the left lower limb, which was identified as a primary cutaneous diffuse large B‐cell lymphoma (PCLBCL), leg type, on biopsy. The patient also showed complications of hepatomegaly, endocrinopathy, edema, skin change, and polyneuropathy without monoclonal plasma cell proliferative disorder, and was therefore diagnosed with POEMS‐like syndrome owing to the lack of monoclonal plasma cell proliferative disorder. Levels of serum vascular endothelial growth factor (VEGF) and interleukin‐6 (IL‐6) were high with the lymphoma cells immunostained positively for VEGF and IL‐6. To the best of our knowledge, this is the first case report of PCLBCL, leg type, with POEMS‐like syndrome. The findings in this case suggest that the symptoms of POEMS‐like syndrome might be caused by the cytokines produced by the lymphoma cells. Furthermore, a wider range of diagnostic criteria associated with the result of abnormal secretion of cytokine may have to be considered for the diagnosis and evaluation of patients with possible POEMS syndrome, as against the present criteria specifying monoclonal plasma cell proliferative disorder as the essential criterion.     

BCL6 gene rearrangements also occur in marginal zone B-cell lymphoma

Marginal zone B-cell lymphoma (MZBCL) represents a distinct subtype of B-cell non-Hodgkin's lymphoma (NHL) which has been recently recognized and defined as a disease entity. Cytogenetically, these lymphomas reveal a high prevalence of trisomy 3, and recent data obtained by comparative genomic hybridization indicate that the chromosomal regions 3q21-23 and 3q25-29 might be of particular pathogenetic significance. We identified structural chromosomal abnormalities involving the region 3q27 and rearrangements of the BCL6 proto-oncogene in three out of 34 (9%) well-defined cases of extranodal, nodal and splenic MZBCL using cytogenetic analysis, Southern blot, and fluorescence in situ hybridization (FISH). All three cases were characterized by a t(3;14)(q27;q32). Two of them showed additional chromosomal abnormalities including trisomy 3, which was found in one case. The patients displayed extranodal disease and did not demonstrate any striking clinical and histological differences when compared with MZBCL lacking BCL6 rearrangement. The present study for the first time demonstrates the occurrence of t(3;14)/ BCL6 gene rearrangement in MZBCL, thus suggesting a role of the BCL6 proto-oncogene in the pathogenesis of MZBCL.     

Bcl-6 gene hypermutations in diffuse large B-cell lymphoma of primary gastric origin

p18^INK4C, a cyclin-dependent kinase inhibitor, is a homologue of p15^INK4B and p16^INK4A which are frequently altered in a variety of malignancies. We searched for structural alterations of the p18^INK4C gene in 44 adult T-cell leukaemias (ATLs), 101 non-Hodgkin's lymphomas (NHLs), two polyclonal B-cell proliferations, seven ATL cell lines and seven leukaemia/lymphoma cell lines, by Southern blot and polymerase chain reaction–single-strand conformation polymorphism (PCR-SSCP) analyses. No genomic alterations of the p18^INK4C gene were found in any of the samples. By RT-PCR, p18^INK4C was not expressed in three of five ATL cell lines, whereas it was expressed in all the non-ATL leukaemia/lymphoma cell lines. Tax did not inhibit the expression of p18^INK4C in tax-expressing Jurkat cells.