Frequent occurrence of deletions in primary mediastinal B-cell lymphoma

Primary mediastinal B-cell lymphoma (PMBCL) is a distinct subtype of diffuse large B-cell lymphoma. PMBCL has been previously studied with a variety of genomic techniques resulting in frequent detection of chromosomal gains; however, chromosomal losses have been rarely reported. This finding contrasts many other types of lymphoma, in which deletions are common. We hypothesize that segmental losses do exist but may have escaped detection by methods used in the previous studies. Using array comparative genomic hybridization to a tiling-resolution microarray encompassing the entire human genome, PMBCL samples were analyzed for genomic copy number alterations. An almost equal number of gains and losses of chromosomal material were detected throughout the genome (216 vs. 193, respectively). A selection of these DNA copy number alterations were confirmed by quantitative real-time PCR. Recurrent gains were detected at all previously reported regions of gain, including 9p seen in approximately 70% of cases. Recurrent chromosomal losses were observed at 1p, 3p, 4q, 6q, 7p, and 17p, with a novel event at 1p13.1-p13.2 representing the most frequent at 42% of cases analyzed. We conclude that consistent losses are present in the PMBCL genome. Given the similar frequency of losses to that of segmental gains of DNA, they are likely to play an important role in the pathogenesis of PMBCL.     

Molecular basis of aggressive disease in chronic lymphocytic leukemia patients with 11q deletion and trisomy 12 chromosomal abnormalities

In B-cell chronic lymphocytic leukemia (CLL), Rai stage, immunoglobulin gene mutational status, chromosomal abnormalities, CD38 and ZAP-70 expression were used as prognostic markers. In this study, to understand the molecular basis of chromosomal abnormalities leading to tumor progression, 90 CLL patients were grouped into poor prognosis (with 11q deletion and trisomy 12) and good prognosis (with normal karyotype and 13q deletion) and their clinical outcome was assessed. Gene expression profiles of 35 CLL samples with poor outcome (11q deletion, n=9; trisomy 12, n=5) and good outcome (13q deletion, n=13; normal karyotype, n=8) were analyzed using oligonucleotide microarray. Significance analysis of microarray (SAM) identified 27 differentially expressed genes between these two subgroups with significant overexpression of ATF5 and underexpression of CDC16, PCDH8, SLAM, MNDA and ATF2 in CLL patients with poor outcome. ATF5 gene expression in CLL was further studied because of its role in the regulation of cell cycle progression/differentiation and apoptosis. The overexpression of ATF5 was confirmed by real-time PCR using 39 CLL samples from the poor and good outcome groups. ATF5 was significantly (p<0.001) overexpressed in the poor outcome group. Furthermore, ATF5 expression was significantly higher in the 11q deletion as well as trisomy 12 group alone compared to the 13q deletion and normal karyotype groups. ATF5 overexpression was also associated with significantly (p=0.04) shorter time to treatment. Similarly, expression of five underexpressed genes also correlated with longer time to treatment. Thus, this report demonstrates that ATF5 may be one of the key genes involved in increased proliferation and survival in 11q deletion or trisomy 12, whereas CD16, CD86, SLAM, MNDA and ATF2 may be involved in the decreased proliferation of CLL cells with 13q deletion or normal karyotype.     

Molecular diagnosis of primary mediastinal B cell lymphoma identifies a clinically favorable subgroup of diffuse large B cell lymphoma related to Hodgkin lymphoma

Using current diagnostic criteria, primary mediastinal B cell lymphoma (PMBL) cannot be distinguished from other types of diffuse large B cell lymphoma (DLBCL) reliably. We used gene expression profiling to develop a more precise molecular diagnosis of PMBL. PMBL patients were considerably younger than other DLBCL patients, and their lymphomas frequently involved other thoracic structures but not extrathoracic sites typical of other DLBCLs. PMBL patients had a relatively favorable clinical outcome, with a 5-yr survival rate of 64% compared with 46% for other DLBCL patients. Gene expression profiling strongly supported a relationship between PMBL and Hodgkin lymphoma: over one third of the genes that were more highly expressed in PMBL than in other DLBCLs were also characteristically expressed in Hodgkin lymphoma cells. PDL2, which encodes a regulator of T cell activation, was the gene that best discriminated PMBL from other DLBCLs and was also highly expressed in Hodgkin lymphoma cells. The genomic loci for PDL2 and several neighboring genes were amplified in over half of the PMBLs and in Hodgkin lymphoma cell lines. The molecular diagnosis of PMBL should significantly aid in the development of therapies tailored to this clinically and pathogenetically distinctive subgroup of DLBCL.     

Salvage therapy for relapsed or refractory non-Hodgkin's lymphoma utilizing autologous bone marrow transplantation

PURPOSE: Our objective was to evaluate the impact of high-dose therapy and autologous bone marrow transplantation as salvage treatment for recurrent non-Hodgkin's lymphoma in a defined group of patients from the Nebraska Lymphoma Study Group. DESIGN: Patients treated initially by oncologists from the Nebraska Lymphoma Study Group between January 1983 and July 1987 who subsequently underwent autologous bone marrow transplantation for recurrent or refractory disease were evaluated for treatment outcome. PATIENTS: Twenty-five patients with relapsed or refractory non-Hodgkin's lymphoma underwent high-dose therapy and autologous stem cell infusion in the time period reviewed. An initial doxorubicin (Adriamycin)-containing chemotherapy regimen had failed in all patients. The most favorable subgroup included 17 patients who were less then 60 years of age and had received no chemotherapy beyond their initial doxorubicin-containing regimen when referred for bone marrow transplantation. RESULTS: The complete response rate to the high-dose therapy was 52%, with an actuarial five-year disease-free survival of all patients treated of 40%. The overall survival at five years was 46%. CONCLUSIONS: High-dose chemo-radiotherapy, followed by infusion of autologous hematopoietic stem cells, can effectively function as salvage therapy in a significant number of patients in whom primary chemotherapy regimens for non-Hodgkin's lymphoma fail. This treatment approach appears to offer superior results when compared with the reported outcome for patients treated with salvage chemotherapy administered at conventional doses.     

Oligonucleotide microarrays demonstrate the highest frequency of ATM mutations in the mantle cell subtype of lymphoma

Mutations have been described in the ataxia telangiectasia mutated (ATM) gene in small numbers of cases of lymphoid neoplasia. However, surveys of the ATM mutation status in lymphoma have been limited due to the large size (62 exons) and complex mutational spectrum of this gene. We have used microarray-based assays with 250,000 oligonucleotides to screen lymphomas from 120 patients for all possible ATM coding and splice junction mutations. The subtypes included were diffuse large B cell, mantle cell, immunoblastic large B cell, follicular, posttransplant lymphoproliferative disorder, and peripheral T cell lymphoma. We found the highest percentage of ATM mutations within the mantle cell (MCL) subtype (43%, 12 of 28 cases), followed by a lower level (10% of cases) in the other subtypes. A frame-shift ATM mutation was found in one peripheral T cell lymphoma patient. In six MCL cases examined, four ATM variants were due to somatic mutation in the tumor cells whereas two others seemed to be germ-line in origin. There was no difference in p53 mutation status in the ATM mutant and wild-type groups of MCL. There was no statistically significant difference in the median overall survival of patients with wild-type vs. mutated ATM in MCL. Additional mutational and functional analyses are needed to determine whether ATM mutations contribute to the development and progression of MCL or are just the consequence of genomic instability in MCL.     

Role of the B domain for factor VIII and factor V expression and function

Factor V and factor VIII are homologous cofactors in the blood coagulation cascade that have the domain structure A1-A2-B-A3-C1-C2, of which the B domain has extensively diverged. In transfected COS-1 monkey cells, expression of factor VIII is approximately 10-fold less efficient than that of factor V, primarily because of inefficient protein secretion and, to a lesser extent, reduced mRNA expression. To study the functional significance and effect of the B domain on expression and activity, chimeric cDNAs were constructed in which the B domains of factor V and factor VIII were exchanged. Expression of a factor VIII chimera harboring the B-domain of factor V yielded a fully functional factor VIII molecule that was expressed twofold more efficiently than wild-type factor VIII because of increased mRNA expression. Thus, sequences within the factor VIII B domain were not responsible for the inefficient secretion of factor VIII compared with factor V. Expression of a factor V chimera harboring the B domain of factor VIII was slightly reduced compared with wild-type factor V, although the secreted molecule had significantly reduced procoagulant activity correlating with dissociated heavy and light chains and resistance to thrombin activation. Interestingly, the factor V chimera containing the factor VIII B domain was efficiently activated by Russell's viper venum (RVV). A factor V B domain deletion (residues 710- 1545) molecule also exhibited significantly reduced procoagulant activity caused by resistance to thrombin cleavage and activation, although this molecule was activatable by RVV. These results show that, in contrast to factor VIII, thrombin activation of factor V requires sequences within the B domain. In addition, thrombin activation of factor V occurs through a different mechanism than activation by RVV.     

Systemic anaplastic large-cell lymphoma: results from the non-Hodgkin's lymphoma classification project

Anaplastic large-cell lymphoma (ALCL) is a heterogeneous process that may have a T-cell, B-cell, or indeterminant (null) phenotype and which may or may not express the anaplastic lymphoma kinase (ALK) oncoprotein. Because the clinical significance of these variants of ALCL is unclear, we evaluated the cases of ALCL-T/null and ALCL-B identified in the Non-Hodgkin's Lymphoma Classification Project. We evaluated 1,378 cases of non-Hodgkin's lymphoma (NHL), and a consensus diagnosis of ALCL-T/null was made in 33 patients (2.4%) with a diagnostic accuracy of 85%. Compared to 96 patients with other forms of peripheral T-cell lymphoma (PTCL), those with ALCL-T/null were significantly younger, less likely to have advanced-stage disease or bone marrow involvement, more likely to have a low International Prognostic Index score, and had a significantly better survival. Among those with ALCL-T/null, there were no significant differences in the clinical features or survival on the basis of ALK expression. A consensus diagnosis of ALCL-B was made in 15 patients (1.1%), and the diagnostic accuracy was 67%. However, compared to 366 patients with other forms of diffuse large B-cell lymphoma (DLBCL), those with ALCL-B were no different with regard to clinical features or survival. We conclude that patients with ALCL-T/null have favorable prognostic features and excellent survival and should be separated from those with other forms of PTCL for prognostic and therapeutic purposes. In contrast, patients with ALCL-B appear to be similar to those with other forms of DLBCL.     

Outcome of autologous transplantation for mantle cell lymphoma: a study by the European Blood and Bone Marrow Transplant and Autologous Blood and Marrow Transplant Registries

Mantle cell lymphoma (MCL) has an aggressive clinical course with a median survival < 3 years and is incurable with conventional chemotherapy. A large multicentre study with adequate follow-up may clarify the role of significant factors affecting outcome in autologous stem cell transplantation for MCL. Patients receiving an autologous transplant for MCL between 1988 and 1998, and reported to the European Blood and bone Marrow Transplant (EBMT) registry or Autologous Blood and Marrow Transplant Registry (ABMTR), were included. Expert haematopathology review was required on all identified patients. Disease and transplant details were requested from the transplant centres, and the final cohort of patients with verified pathology, adequate clinical information and follow-up was analysed. One hundred and ninety-five patients were included in the analyses (149 EBMT, 46 ABMTR) with a median follow-up of 3.9 years. The 2 year and 5 year overall survival were 76% and 50%, and progression free survival was 55% and 33% respectively. Disease status at transplant was the most significant factor affecting survival: patients with chemosensitive disease but not in first complete remission (CR1) were 2.99 times (95% CI: 1.66-5.38, P < 0.001) more likely to die than patients transplanted in CR1. Autologous transplantation probably improves survival in patients with MCL especially if performed in first CR.     

Burkitt lymphoma risk in U.S. solid organ transplant recipients

Case reports of Burkitt lymphoma (BL) in transplant recipients suggest that the risk is markedly elevated. Therefore, we investigated the incidence of BL in 203,557 solid organ recipients in the U.S. Transplant Cancer Match Study (1987–2009) and compared it with the general population using standardized incidence ratios. We also assessed associations with demographic and clinical characteristics, and treatments used to induce therapeutic immunosuppression. BL incidence was 10.8 per 100,000 person‐years, representing 23‐fold (95% confidence interval (CI) 19–28) greater risk than in the general population, and it peaked 3–8 years after the time of transplantation. In adjusted analyses, BL incidence was higher in recipients transplanted when <18 vs. ≥35 years (incidence rate ratio [IRR] 3.49, 95% CI 2.08–5.68) and in those transplanted with a liver (IRR 2.91, 95% CI 1.68–5.09) or heart (IRR 2.39, 95% CI 1.30–4.31) compared with kidney. BL incidence was lower in females than males (IRR 0.45, 95% CI 0.28–0.71), in blacks than whites (IRR 0.33, 95% CI 0.12–0.74), in those with a baseline Epstein‐Barr virus (EBV)‐seropositive versus EBV‐seronegative status (IRR 0.34, 95% CI 0.13–0.93), and in those treated with azathioprine (IRR 0.56, 95% CI 0.34–0.89) or corticosteroids (IRR 0.48, 95% CI 0.29–0.82). Tumors were EBV‐positive in 69% of 32 cases with results. EBV positivity was 90% in those aged <18 years and 59% in those aged 18+ years. In conclusion, BL risk is markedly elevated in transplant recipients, and it is associated with certain demographic and clinical features. EBV was positive in most but not all BL cases with results. Am. J. Hematol. 88:245–250, 2013. © 2012 Wiley Periodicals, Inc.     

B‐cell lymphoma,unclassifiable, with features intermediate between diffuse large B‐cell lymphoma and burkitt lymphoma: study of 39 cases

B‐cell lymphoma, unclassifiable (B‐UCL), with features intermediate between diffuse large B‐cell lymphoma and Burkitt lymphoma, is a poorly characterized entity. Therefore, we investigated cases of B‐UCL treated by the Nebraska Lymphoma Study Group (NLSG). We searched the NLSG registry for years 1985–2010 for cases of B‐UCL. Immunohistochemical stains and fluorescence in situ hybridization studies for MYC, BCL2 and BCL6 gene rearrangements were performed. Among the 39 cases studied, 54% were male and 46% were female, with a median age of 69 years. The majority of patients presented with advanced‐stage disease (62%) and had high (3–5) International Prognostic Index (IPI) scores (54%). The median overall survival (OS) was only 9 months and the 5‐year OS was 30%. Patients with low IPI scores (0–2) had a better survival than those with high scores (3–5). The cases were genetically heterogeneous and included 11 ‘double‐hit’ lymphomas with rearrangements of both MYC and BCL2 or BCL6. None of the immunohistochemical or genetic features was predictive of survival. This B‐cell lymphoma is a morphologically‐recognizable entity with a spectrum of genetic abnormalities. New and better treatments are needed for this aggressive lymphoma.