Search

P>Despite recent therapeutic improvements, the clinical course of diffuse large B-cell lymphoma (DLBCL) still differs considerably among patients. We conducted this retrospective multi-centre study to evaluate the impact of genomic aberrations detected using a high-density genome wide-single nucleotide polymorphism-based array on clinical outcome in a population of DLBCL patients treated with R-CHOP-21 (rituximab, cyclophosphamide, doxorubicine, vincristine and prednisone repeated every 21 d). 166 DNA samples were analysed using the GeneChip Human Mapping 250K NspI. Genomic anomalies were analysed regarding their impact on the clinical course of 124 patients treated with R-CHOP-21. Unsupervised clustering was performed to identify genetically related subgroups of patients with different clinical outcomes. Twenty recurrent genetic lesions showed an impact on the clinical course. Loss of genomic material at 8p23.1 showed the strongest statistical significance and was associated with additional aberrations, such as 17p- and 15q-. Unsupervised clustering identified five DLBCL clusters with distinct genetic profiles, clinical characteristics and outcomes. Genetic features and clusters, associated with a different outcome in patients treated with R-CHOP, have been identified by arrayCGH.

Richter syndrome (RS) represents the development of diffuse large B-cell lymphoma in the context of chronic lymphocytic leukemia. The scarcity of biologic information about RS has hampered the identification of molecular predictors of RS outcome. We addressed this issue by performing a comprehensive molecular characterization of 86 pathologically proven RS. TP53 disruption (47.1%) and c-MYC abnormalities (26.2%) were the most frequent alterations, whereas common genetic lesions of de novo diffuse large B-cell lymphoma were rare or absent. By multivariate analysis, lack of TP53 disruption (hazard ratio, 0.43; P = .003) translated into significant survival advantage with 57% reduction in risk of death. An algorithm based on TP53 disruption, response to RS treatment, and Eastern Cooperative Oncology Group performance status had 80.9% probability of correctly discriminating RS survival (c-index = .809). RS that were clonally unrelated to the paired chronic lymphocytic leukemia phase were clinically and biologically different from clonally related RS because of significantly longer survival (median, 62.5 months vs 14.2 months; P = .017) and lower prevalence of TP53 disruption (23.1% vs 60.0%; P = .018) and B-cell receptor stereotypy (7.6% vs 50.0%; P = .009). The molecular dissection of RS into biologically distinct categories highlights the genetic heterogeneity of this disorder and provides clinically relevant information for refining the prognostic stratification of patients.

Richter's syndrome (RS) represents the transformation of chronic lymphocytic leukaemia (CLL) to aggressive lymphoma and is mostly represented by diffuse large B-cell lymphoma (DLBCL), with a post-germinal centre (GC) phenotype, clonally related to the pre-existing CLL. RS has a very poor prognosis and its pathogenetic mechanisms are poorly understood. In order to gain additional hints in RS pathogenesis, we performed a genome-wide DNA profiling study of 13 RS phases and eight matched CLL phases using the Affymetrix Human Mapping 250K NspI SNP arrays. Individual genomic profiles were heterogeneous, with no individual lesions occurring in more than half of the cases. However, several observations suggest that MYC pathway might be involved in RS. The 13q13.3-qter region containing MIRHG1 (MIR-17-92), a cluster of microRNA interacting with c-MYC, was acquired at the time of transformation. The 13q gain was coupled with the gain of c-MYC and loss of TP53. Translocation of c-MYC was acquired at transformation in a fraction of cases and this event appeared mutually exclusive with gain of MIRHG1. MYCN, a c-MYC homologue, was also recurrently gained. By comparing RS with 48 de nova DLBCL, RS presented a significantly lower prevalence of deletions affecting the PRDM1 and TNFAIP3, genes on 6q, known to be associated with a post-GC phenotype. In conclusion, the genomic profile of RS seems to differ from what observed in de novo DLBCL and in other transformed DLBCL. Genomic lesions occurring in RS are heterogeneous suggesting the existence of different RS subsets, possibly due to different transforming mechanisms. A deregulation of MYC pathway might represent one of the main transformation events in the pathogenesis of a subset of RS clonally related to the previous CLL. Copyright (C) 2009 John Wiley & Sons, Ltd.

Marginal zone B-cell lymphomas (MZLs) have been divided into 3 distinct subtypes (extranodal MZLs of mucosa-associated lymphoid tissue [MALT] type, nodal MZLs, and splenic MZLs). Nevertheless, the relationship between the subtypes is still unclear. We performed a comprehensive analysis of genomic DNA copy number changes in a very large series of MZL cases with the aim of addressing this question. Samples from 218 MZL patients (25 nodal, 57 MALT, 134 splenic, and 2 not better specified MZLs) were analyzed with the Affymetrix Human Mapping 250K SNP arrays, and the data combined with matched gene expression in 33 of 218 cases. MALT lymphoma presented significantly more frequently gains at 3p, 6p, 18p, and del(6q23) (TNFAIP3/A20), whereas splenic MZLs was associated with del(7q31), del(8p). Nodal MZLs did not show statistically significant differences compared with MALT lymphoma while lacking the splenic MZLs-related 7q losses. Gains of 3q and 18q were common to all 3 subtypes. del(8p) was often present together with del(17p) (TP53). Although del(17p) did not determine a worse outcome and del(8p) was only of borderline significance, the presence of both deletions had a highly significant negative impact on the outcome of splenic MZLs.

P>To characterize diffuse large B-cell lymphoma (DLBCL) with chromosome 7 gains, we combined clinical data with genomic, RNA and miRNA profiling. Gains were associated with age > 60 years, female gender, a trend for higher complete response rate, lower death rate, and better overall survival in patients treated with R-CHOP. Lesions were inversely associated with bone marrow involvement and number of extra-nodal sites. Differentially expressed transcripts were enriched of genes belonging to specific pathways and miRNAs targets. MIR96, MIR182, MIR589, MIR25 were shown significantly up-regulated in 7q+ DLBCL by real-time PCR.

Bone marrow ( BM) involvement in diffuse large B-cell lymphoma (DLBCL) can be morphologically discordant from the primary tumor. Concordant BM infiltration has been shown associated with a poorer outcome in patients treated with CHOP. In order to evaluate tumor-related factors leading to BM involvement in DLBCL, we performed an integrated analysis of i) genomic profiles obtained with a high-density genome wide SNP-based arrays ii) immunomorphological and iii) clinical data from 133 patients uniformly treated with R-CHOP. BM infiltration was found in 27 of 133 ( 20%) cases; and it was concordant in 18/27 (67%) cases. Concordant infiltration, but not discordant, influenced negatively OS, PFS and DFS and was associated with higher serum LDH, lower CR and higher PD rates. No association with cell of origin was found between BM+ and BM-DLBCL. As compared with BM- cases, BM+ DLBCL showed absence of 7q gain. Copyright (C) 2010 John Wiley & Sons, Ltd.

Post-transplant lymphoproliferative disorders (PTLD) are complications of solid organ transplantation associated with severe morbidity and mortality. Diffuse large B-cell lymphoma (DLBCL) represents the most common form of monomorphic PTLD. We studied 44 cases of post-transplant DLBCL (PT-DLBCL) with high-density genome wide single nucleotide polymorphism-based arrays, and compared them with 105 cases of immunocompetent DLBCL (IC-DLBCL) and 28 cases of Human Immunodeficiency Virus-associated DLBCL (HIV-DLBCL). PT-DLBCL showed a genomic profile with specific features, although their genomic complexity was overall similar to that observed in IC- and HIV-DLBCL. Among the loci more frequently deleted in PT-DLBCL there were small interstitial deletions targeting known fragile sites, such as FRA1B, FRA2E and FRA3B. Deletions at 2p16.1 (FRA2E) were the most common lesions in PT-DLBCL, occurring at a frequency that was significantly higher than in IC-DLBCL. Genetic lesions that characterized post-germinal center IC-DLBCL were under-represented in our series of PT-DLBCL. Two other differences between IC-DLBCL and PT-DLBCL were the lack of del(13q14.3) (MIR15/MIR16) and of copy neutral LOH affecting 6p [major histocompatibility complex (MHC) locus] in the latter group. In conclusion, PT-DLBCL presented unique features when compared with IC-DLBCL. Changes in PT-DLBCL were partially different to those in HIV-DLBCL, suggesting different pathogenetic mechanisms in the two conditions linked to immunodeficiency.

Abstract 670 Richter syndrome (RS) represents the transformation of chronic lymphocytic leukemia (CLL) to aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). Knowledge of the genetic lesions associated with RS is scant and represents the aim of this study. The study was based on 47 RS cases (all DLBCL). In 32 cases, paired CLL/RS samples were available (28 clonally related and 4 clonally unrelated). In 15 cases, the sole RS sample was analysed. According to CD10/BCL6/MUM1 immunohistochemistry expression pattern, 43/47 (91.5%) RS were classified as non-germinal center DLBCL. At diagnosis, 37.8% RS showed ECOG PS >1, 77.8% Binet stage B-C, 95.7% Ann Arbor stage III-IV, 44.4% B symptoms, 45.7% tumor size >5 cm, 32.6% involvement of >1 extranodal site, 66.7% LDH elevation, and 28.9% platelets Disclosures: No relevant conflicts of interest to declare.

Abstract 3957 Poster Board III-893 BACKGROUND Despite recent therapeutic improvements, the clinical course of DLBCL still differs considerably among patients. Here, we present the final results of a study to identify distinct DLBCL subgroups in patients treated with R-CHOP. METHODS DNA from 166 frozen DLBCL samples (PMBL,HIV-related DLBCL, post-transplant DLBCL and Richter's Syndromes were excluded) was analyzed with Affymetrix Human Mapping 250K arrays. Affymetrix U133 PLUS 2.0 gene expression profiles (GEP) were available for 54 cases. An optimized non-negative matrix factorization (NMF) was used for unsupervised clustering. The impact of the recurrent lesions on OS, PFS and DFS was evaluated with the log-rank test followed by multiple test correction (MTC). RESULTS 20 lesions showed a statistical significant impact on OS. Only 8p23.1 loss maintained its significance after MTC and was associated with additional aberrations, such as 17p- and 15q-. Unsupervised clustering identified 5 clusters with distinct genetic profiles, clinical characteristics and outcome: 1 (61/166, 37%), 2 (22/166, 13%), 3 (5/166, 4%), 4 (29/166, 17%), 5 (7/166, 6%). Cluster 1 was characterized by a heterogeneous genomic profile, lacking the most recurrent lesions. When compared to cluster 2 and 4, there were more HCV infections (9/38, 24% vs 1/12, 8% and 0/20; p=0.014) and bone marrow involvement (16/57, 28% vs 1/19, 5% and 2/24, 8%; p=0.008). GEP and morphology data suggested that cluster 1 could represent DLBCL with a high content of infiltrating T-cells, partially explaining the low rate of aberrations. This cluster has characteristics similar to the “host response” cluster previously identified by Monti et al., 2005. The outcome was poor with a high relapse rate (13/49, 26%) and a 5-yr OS of 76%. Cluster 2 (1q+/3q+/6q-/17p-) had also a relatively poor OS 80%. Cluster 4 (7+/12+) had a good outcome with a 5-yr OS of 92%. Clusters 2 and 4 showed differences in the number of pts with a high IPI-score (9/16, 56% vs. 7/26, 27%; p=0.057) and in single IPI factors, CR-rate (17/22, 77% vs. 25/29, 86%) and relapse rate (5/17, 29% vs. 2/25, 8%; p= 0.068). Cluster 3 (6q-/9-/11q+) had a trend for a good outcome. Instead, cluster 5 (3q+/11q+/18q+/6q-/8p-/15q-/17p-) showed a poor outcome. Clusters 2 and 4 were similar to ABC and GCB, respectively. CONCLUSIONS ArrayCGH provides the capability to identify genetic features and clusters, associated with a different outcome in patients treated with R-CHOP. The 8p23.1 locus should be investigated further for a gene that may be important in the pathogenesis of DLBCL. Disclosures: No relevant conflicts of interest to declare.

Background and Aim. In the current WHO classification, marginal zone B-cell lymphomas (MZL) have been divided into three distinct subtypes (extranodal, EMZL; nodal, NMZL; splenic, SMZL) according to clinical, pathological and cytogenetic features, however the relationship between any of the different subtypes is still unclear. We thus performed a comprehensive analysis of genomic DNA copy number changes in a very large series of MZL cases with the aim of addressing this question. Materials and Methods. DNA extracted from frozen samples of MZL was analyzed with Affymetrix Human Mapping 250K SNP arrays. Results. Samples from 193 patients with MZL (23 NMZL, 63 EMZL, 84 SMZL and 23 not better specified MZL) from 15 Institutions were analyzed. Among EMZL, main primary sites were orbital adnexa in 28%, GI-tract in 16%, lung and salivary glands 5% each. Overall, MZL displayed more recurrent deletions than gains. Gains of 3q and 18 gains were common to all three MZL subtypes as were losses at 1p32.3-pter, 7p22.1-pter, 7q11.21–q11.23, 9q33.3-qter, 16p, 17p and 19. EMZL had significantly more gains at 3p14.2-pter, 6p and 7q31.3-qter and losses at 6q15, 6q23.3 and 14q11.2 than SMZL. Conversely, the latter had deletions of 7q31.32-qter and 14q23.3–q32.13 more frequently than EMZL. NMZL profiles showed the EMZL-specific 6q losses and the SMZL-related 7q losses at very low frequency while presented recurrent gains of chromosome 11, which was unique of NZML among the three subtypes. The 6q23.3 region contains the gene coding for TNFAIP3/A20, a negative regulator of the NFkB pathway. In SMZL a minimal deleted region was observed in 7q32.1. Regarding chromosome 3, gains targeted the whole chromosome in EMZL while, in SMZL and NMZL, the long arm was more commonly affected. Conclusions. EMZL, NMLZ and SMLZL share genetic alterations, which differ from other B-cell lymphomas. However subtype-specific genetic lesions are observed. In particular, gains of 6p and losses of 6q23.3 (TNFAIP3) are specific for EMZL, and 7q31-qter for SMZL.