Plasmablastic lymphoma (PBL) is an aggressive lymphoma characterized by a terminally differentiated B-cell phenotype that usually occurs in immunocompromised or elderly patients. Although the clinical and pathological characteristics of these tumours have been defined the genetic alterations involved in their pathogenesis are not well known. In this study we have investigated the chromosomal alterations of MYC, BCL2, BCL6, MALT1, PAX5, and IGH loci using fluorescence in situ hybridization (FISH) in 42 plasmablastic lymphomas (PBL) and 3 extracavitary primary effusion lymphomas (PEL). MYC rearrangements were identified in 20 of 41 (49%) PBL and the immunoglobulin (IG) genes were the partners in most tumours. MYC rearrangements were more common in EBV-positive (14 of 19, 74%) than EBV-negative (9 of 21, 43%) tumours (p < 0.05). No rearrangements of BCL2, BCL6, MALT1 or PAX5 were detected in any PBL but gains of these loci were observed in 31-41% of the cases examined. Twelve of the 40 PBL in which 3 or more loci could be investigated had multiple simultaneous gains in 3 or more loci. No differences in the survival of the patients according to MYC were observed but the four patients with the longest survival (>50 months) had no or low number of gains (<3). No rearrangements of any of these loci were seen in PEL. In conclusion, PBL are genetically characterized by frequent IG/MYC translocations and gains in multiple chromosomal loci. The oncogenic activation of MYC in these lymphomas may be an important pathogenetic element associated with EBV infection.

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In the present series, the primary site of disease was associated with particular clinicopathologic features and outcome, though the latter largely depended on other factors.

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PCSM-TCL is a heterogeneous group of tumors with differentiated clinical and pathological characteristics with impact in the outcome of the patients.

Genome studies of diffuse large B-cell lymphoma (DLBCL) have revealed a large number of somatic mutations and structural alterations. However, the clinical significance of these alterations is still not well defined. In this study, we have integrated the analysis of targeted next-generation sequencing of 106 genes and genomic copy number alterations (CNA) in 150 DLBCL. The clinically significant findings were validated in an independent cohort of 111 patients. Germinal center B-cell and activated B-cell DLBCL had a differential profile of mutations, altered pathogenic pathways and CNA. Mutations in genes of the NOTCH pathway and tumor suppressor genes (TP53/CDKN2A), but not individual genes, conferred an unfavorable prognosis, confirmed in the independent validation cohort. A gene expression profiling analysis showed that tumors with NOTCH pathway mutations had a significant modulation of downstream target genes, emphasizing the relevance of this pathway in DLBCL. An in silico drug discovery analysis recognized 69 (46%) cases carrying at least one genomic alteration considered a potential target of drug response according to early clinical trials or preclinical assays in DLBCL or other lymphomas. In conclusion, this study identifies relevant pathways and mutated genes in DLBCL and recognizes potential targets for new intervention strategies.

BackgroundDiffuse large B-cell lymphoma is a clinically and molecularly heterogeneous disease. Gene expression profiling studies have shown that the tumor microenvironment affects survival and that the angiogenesis-related signature is prognostically unfavorable. The contribution of histopathological microvessel density to survival in diffuse large B-cell lymphomas treated with immunochemotherapy remains unknown. The purpose of this study is to assess the prognostic impact of histopathological microvessel density in two independent series of patients with diffuse large B-cell lymphoma treated with immunochemotherapy. Design and MethodsOne hundred and forty-seven patients from the Leukemia Lymphoma Molecular Profiling Project (training series) and 118 patients from the Catalan Lymphoma-Study group-GELCAB (validation cohort) were included in the study. Microvessels were immunostained with CD31 and quantified with a computerized image analysis system. The stromal scores previously defined in 110 Leukemia Lymphoma Molecular Profiling Project cases were used to analyze correlations with microvessel density data. ResultsMicrovessel density significantly correlated with the stromal score (r=0.3209; P<0.001). Patients with high microvessel density showed significantly poorer overall survival than those with low microvessel density both in the training series (4-year OS 54% vs. 78%; P=0.004) and in the validation cohort (57% vs. 81%; P=0.006). In multivariate analysis, in both groups high microvessel density was a statistically significant unfavorable prognostic factor independent of international prognostic index [training series: international prognostic index (relative risk 2.7; P=0.003); microvessel density (relative risk 1.96; P=0.002); validation cohort: international prognostic index (relative risk 4.74; P<0.001); microvessel density (relative risk 2.4; P=0.016)]. ConclusionsThese findings highlight the impact of angiogenesis in the outcome of patients with diffuse large B-cell lymphoma and the interest of evaluating antiangiogenic drugs in clinical trials.

This intensive regimen resulted in moderate CR rate, with manageable toxicity in PTCL. The contribution of ASCT in preventing relapse is debatable. Novel strategies to increase CR warrant investigation.