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Summary Changes in DNA copy number (CN) and DNA methylation represent important aberrations for lymphomas and other cancers. Here, for the first time, we show that the Illumina Infinium Methylation (IIM) assay, although not originally designed for CN profiling, is able to estimate CN changes. We compared the IIM CN profiles to those obtained with a standard technique in a series of diffuse large B-cell lymphomas: the profiles showed a high degree of consensus. The demonstration of CN profiling as an additional function of the IIM assay may impact the choice of platform for methylation profiling of haematological and solid tumours. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigated the involvement of CD79A, EZH2, and CD79B gene mutations in immunodeficiency-related non-Hodgkin lymphomas (ID-NHL). Using polymerase chain reaction amplification and direct sequencing, the study identified only EZH2 mutations in 3/116 ID-NHL primary samples. It notes that among the immunocompetent hosts' aggressive NHL, EZH2 mutations are selectively confined to cases of diffuse large B-cell lymphoma (DLBCL) with a germinal centre (GC) phenotype.

Non-Hodgkin lymphomas (NHL) represent a frequent complication of human immunodeficiency virus (HIV) infection. To elucidate HIV-NHL pathogenesis, we performed a genome-wide DNA profiling based on a single nucleotide polymorphism-based microarray comparative genomic hybridization in 57 HIV-lymphomas and, for comparison, in 105 immunocompetent diffuse large B-cell lymphomas (IC-DLBCL). Genomic complexity varied across HIV-NHL subtypes. HIV-Burkitt lymphoma showed a significantly lower number of lesions than HIV-DLBCL ( P = 0·032), whereas the median number of copy number changes was significantly higher in Epstein–Barr virus negative (EBV-) HIV-DLBCL (42·5, range 8–153) compared to EBV+ cases (22; range 3–41; P = 0·029). Compared to IC-DLBCL, HIV-DLBCL displayed a distinct genomic profile with no gains of 18q and specific genetic lesions. Fragile sites-associated genes, including FHIT (FRA3B), WWOX (FRA16D), DCC (FRA18B) and PARK2 (FRA6E) were frequently inactivated in HIV-NHL by interstitial deletions, and a significantly higher prevalence of FHIT alterations was observed in HIV-DLBCL compared to IC-DLBCL. The same genes involved by fragile site deletions were also frequently affected by aberrant methylation of regulative regions. [ABSTRACT FROM AUTHOR]

Predictors of chronic lymphocytic leukaemia (CLL) transformation to Richter syndrome (RS) are not established and were investigated in 185 consecutive CLL cases. Actuarial incidence of RS ( n = 17; all diffuse large B-cell lymphomas) at 10 years was 16·2% (95% confidence interval: 8·0–24·4%). At CLL diagnosis, prognosticators of RS by univariate analysis were IGHV homology ≥98% ( P = 0·006), IGHV4-39 usage ( P < 0·001), del13q14 absence ( P = 0·004), expression of CD38 ( P < 0·001) and ZAP70 ( P = 0·004), size ( P < 0·001) and number ( P < 0·001) of lymph nodes, advanced Binet stage ( P = 0·002), and lactate dehydrogenase ( P < 0·001). Multivariate analysis, performed separately for biological and clinical variables, identified CD38 expression [Hazard ratio (HR) = 4·26; P = 0·018], IGHV4-39 usage (HR = 4·29; P = 0·018), and lymph node size ≥3 cm (HR = 9·07; P < 0·001) as independent RS prognosticators. A multivariate model simultaneously analysing biological and clinical variables identified lymph node size ≥3 cm (HR = 6·51; P = 0·001) and del13q14 absence (HR = 4·08; P = 0·031) as independent RS prognosticators. Risk factors of CLL transformation differed from risk factors of CLL progression. These results suggest that CD38 and del13q14 may identify biological subsets of CLL with different RS predisposition. Predominant nodal disease, CD38 expression, IGHV4-39 usage, and absence of del13q14 may help in predicting RS at CLL diagnosis. Close monitoring and a careful biopsy policy are needed in patients carrying transformation risk factors. [ABSTRACT FROM AUTHOR]

Summary: Objective: The aim of this study was to determine the occurrence of polymorphic variants of EBV BamHI fragment Z (BZLF1) promoter zone Zp in tumor and non-tumor-associated EBV. We characterized the Zp region in type A and type B EBV, infecting AIDS-related non-Hodgkin''s lymphomas (AIDS-NHL) and non-malignant lymphoid tissues derived from HIV-positive patients and from healthy individuals. Methods: The Zp region was directly sequenced in 133 EBV-positive DNA samples: 63 AIDS-NHL (32 systemic AIDS-NHL and 31 AIDS-primary central nervous system lymphoma [AIDS-PCNSL]), 30 lymphoid tissues derived from HIV-positive individuals and 40 lymphoid samples derived from healthy individuals. The chi square test was used to assess for statistically significant differences among proportions, and a two-tailed P value ≤0.05 was chosen as statistically significant. Results: We found three polymorphic Zp variants: Zp-P, considered to be the prototype sequence; Zp-V3, that differs from Zp-P for three nucleotide substitutions; and a new variant, Zp-PV, that differs from Zp-P for a single nucleotide substitution. Zp-V3 was significantly associated with AIDS-PCNSL (P <0.001) and with systemic AIDS-NHL (P =0.007), in particular with AIDS-related immunoblastic lymphoma (P <0.001). Moreover, in malignant samples, this variant was also significantly associated with type B EBV (P <0.001). Finally, the new identified Zp-PV variant was isolated in 7 AIDS-PCNSL. Conclusions: The frequency of polymorphisms in the regulatory zone of BZLF1 is different between malignant and non-malignant samples in AIDS patients and may identify EBV subtypes with different transforming activities, including those associated to the pathogenesis of B cell lymphoma. [Copyright &y& Elsevier]

Post-transplant lymphoproliferative disorders (PTLD) are a major complication of solid organ transplantation, representing a cause of severe morbidity and mortality. Apart from Epstein–Barr virus infection, knowledge of the pathogenesis of monoclonal PTLD is limited. Powerful analysis techniques, such as whole genomic DNA profiling (array comparative genomic hybridisation), can improve our understanding of PTLD pathogenesis. Whole genome profiling using the Affymetrix GeneChip Human Mapping 10 k 2·0 was performed on 20 PTLD cases and 25 cases of diffuse large B-cell lymphoma (DLBCL) from immunocompetent patients as a control group. Recurrent lesions were detected among all the samples. Chromosome 18q, 7q, 3q and 12 were the most common gains in the control group. Chromosomes 5p and 11p were commonly gained in PTLD–DLBCL. The latter had frequent losses of 6q, 17p, 1p and 9p. Chromosome 12p was the most frequent target of deletions among PTLD–DLBCL cases. Loss of heterozygosity (LOH) did not always match DNA loss: chromosome 10 seemed to be targeted by uniparental disomy in PTLD. Small deletions and gains, involving both known ( BCL2 and PAX5) and unknown genes ( ZDHHC14), were identified. These data suggest that PTLD share, at a lower frequency, common genetic aberrations with DLBCL from immunocompetent patients. The demonstration of 9p13 amplification emphasises the importance of PAX5 in PTLD. The combination of DNA copy number and LOH assessment lead to the hypothesis that uniparental disomy may be a potential mechanism in B-cell lymphomagenesis. [ABSTRACT FROM AUTHOR]

Primary effusion lymphomas (PELs) are invariably infected by human herpesvirus type 8 (HHV8) and often co-infected by Epstein–Barr virus (EBV). We found that expression of major histocompatibility complex class I (MHC-I) surface molecules was significantly decreased in PEL cells when compared with HHV8 negative lymphomas, irrespective of EBV infection. MHC-I downregulation rendered PEL cells sensitive to recognition and killing by natural killer (NK) cells. Intriguingly, analysis of MHC-I non-restricted cytotoxicity in two PEL patients indicated a reduced NK cell activity when compared with healthy individuals. These data suggest that PEL outgrowth may require an impaired NK cell function. [ABSTRACT FROM AUTHOR]

We investigated the prevalence and prognostic role of CpG island methylation of the reduced folate carrier ( RFC) gene promoter region in primary central nervous system lymphoma (PCNSL) in immunocompetent patients. Genomic DNA from 40 PCNSL was used for methylation-specific polymerase chain reaction and bisulphite genomic sequencing of the RFC promoter region. Human immunodeficiency virus-negative systemic diffuse large B-cell lymphomas (DLBCL) were used as controls ( n = 50). The impact on outcome of RFC promoter methylation was assessed in 37 PCNSL patients treated with high-dose methotrexate (HD-MTX)-based chemotherapy ± radiotherapy. RFC promoter methylation occurred in 12 of 40 (30%) PCNSL and in four of 50 (8%) DLBCL ( P = 0·01). Of 37 PCNSL treated with HD-MTX-based chemotherapy, methylation occurred in nine cases (24%, M-PCNSL), while 28 cases (76%, U-PCNSL) were negative. Three M-PCNSL (33%) and 15 U-PCNSL (54%) achieved complete remission (CR) after primary chemotherapy. Logistic regression confirmed the independent association between CR rate and International Extranodal Lymphoma Study Group score ( P = 0·03), RFC promoter methylation ( P = 0·07) and use of cytarabine ( P = 0·08). The 3-year failure-free survival (FFS) and overall survival for M-PCNSL and U-PCNSL was 0% vs. 31 ± 9% ( P = 0·34) and 0% vs. 31 ± 9% ( P = 0·35) respectively. This is the first study to assess the methylation status of the RFC promoter in human tumour samples. RFC methylation is more common in PCNSL compared with systemic DLBCL, and is associated with a lower CR rate to HD-MTX-based chemotherapy. If confirmed in prospective trials on PCNSL treated with HD-MTX alone, these data may suggest the necessity for alternative strategies in M-PCNSL considering the increased risk of MTX resistance by tumour cells. [ABSTRACT FROM AUTHOR]

The mutator phenotype caused by defects in the mismatch repair system is observed in a subset of solid neoplasms characterized by widespread microsatellite instability-high (MSl-H). It is known to be very rare in non-Hodgkin lymphomas (NHL), whereas mutator NHL is the most frequent tumor subtype in mismatch repair- deficient mice. By screening a series of 603 human NHL with specific markers of the mutator phenotype, we found here 12 MSI-H cases (12/603, 2%). Of interest we demonstrated that this phenotype was specifically associated with immunodeficiency-related lymphomas (ID-RL), because it was observed in both posttransplant lymphoproliferative disorders (9/111, 8.1%) and HIV infection- related lymphomas (3/128, 2.3%) but not in a large series of NHL arising in the general population (0/364) (P < 0.0001). The M5l pathway is known to lead to the production of hundreds of abnormal protein neoantigens that are generated in MSl-H neoplasms by frameshift mutations of a number of genes containing coding microsatellite sequences. As expected, MSI-H ID-RL were found to harbor such genetic alterations in 12 target genes with a putative role in lymphomagenesis. The observation that the MSl-H phenotype was restricted to HIV infection-related lymphomas and posttransplant lymphoproliferative disorders suggests the existence of the highly immunogenic mutator pathway as a novel oncogenic process in lymphomagenesis whose role is favored when host immunosurveillance is reduced. Because MSl-H-positive cases were found to be either Epstein-Barr virus-positive or -negative, the mutator pathway should act synergistically or not with this other oncogenic factor, playing an important role in ID-RL. [ABSTRACT FROM AUTHOR]

Novel N-glycosylation sites are introduced by somatic mutation into the V genes of the majority of follicular lymphomas. Sites are positively selected and rare in normal memory B cells, indicating a potential role in tumour survival in the germinal centre (GC). The incidence of c. 40% in diffuse large B-cell lymphomas (DLBCL) parallels the known heterogenity of the disease. Immunodeficiency-related non-Hodgkin's lymphomas (NHL) include post-transplant lymphoproliferative disorders (PTLD) and acquired immunodeficiency syndrome-related NHL (AIDS-NHL). Most PTLD derive from B cells that carry mutated VH genes and that have completed the GC reaction. All AIDS-NHL carry mutated VH genes and variable features of GC or post-GC cells. To determine if N-glycosylation is a feature of immunodeficiency-related lymphomas, we analysed the VH genes of 19 PTLD and 36 AIDS-NHL. Novel sites were rare in PTLD (4/19), similar to memory B cells ( P = 0·15). AIDS-NHL, including DLBCL and Burkitt's lymphomas (BL), showed heterogeneity with 16 of 36 (44%) having novel sites. The findings indicate no selection of N-glycosylation sites in PTLD, consistent with post-GC features. The variable incidence of N-glycosylation sites in AIDS-NHL mirrors that in DLBCL and sporadic BL of immunocompetent hosts, supporting the known heterogeneity of these disorders, and possibly pointing to distinct routes of tumour development. [ABSTRACT FROM AUTHOR]

Summary. Rituximab (Mabthera) and alemtuzumab (Campath® , Mabcampath® ) are non-conjugated IgG1 therapeutic monoclonal antibodies directed against the CD20 and CD52 surface antigens respectively. They are presently used in the therapy of indolent B-cell non-Hodgkin's lymphoma (B-NHL) and of B-cell chronic lymphocytic leukaemia, and are thought to act mainly through complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC). Here we have analysed the capacity of these two monoclonal antibodies to lyse cell lines of acquired immunodeficiency syndrome (AIDS)-related B-NHL through either complement activation or antibody-dependent cytotoxicity. Rituximab strongly activated both CDC and ADCC against CD20-positive AIDS-NHL cells lines, inducing up to 60–98% and 20% specific lysis respectively. In contrast, alemtuzumab was a poor activator of CDC, even in the AIDS-NHL cell lines expressing high amounts of CD52, leading to a lysis of only 1–30%, whereas it was at least as strong as rituximab in inducing ADCC of the same lines (up to 30% specific lysis). Altogether, these data offer a first in vitro rationale supporting the therapeutic use of rituximab for CD20-positive AIDS-NHL. [ABSTRACT FROM AUTHOR]

Primary effusion lymphoma (PEL) is a peculiar B-cell lymphoma characterized by infection by human herpesvirus type-8/Kaposi sarcoma-associated herpesvirus (HHV-8/KSHV) and by preferential growth in the serous body cavities. Histogenetic studies have suggested that PEL originates from B cells at a late stage of differentiation. In this study, we have investigated PEL for the expression status of MUM1/IRF4 (multiple myeloma 1/interferon regulatory factor 4) protein, which is involved in physiological B-cell maturation and represents a histogenetic marker of late B-cell differentiation. Using multiple detection assays, all cases of PEL (n = 22) were found to express MUM1/IRF4 molecules. MUM1/IRF4 expression was a selective feature of PEL among lymphomas involving the serous body cavities as secondary lymphomatous effusions generally failed to express the protein. In reactive lymphoid tissues, MUM1/IRF4 expression clustered with advanced stages of B-cell differentiation. Comparison of MUM1/IRF4 expression with that of other histogenetic markers defined two phenotypic variants of PEL, i.e. MUM1/IRF4+, CD138/syndecan-1+, B-cell antigen- (20 out of 22 cases) and MUM1/IRF4+, CD138/syndecan-1-, B-cell antigen+ (2 out of 22 cases), suggesting a certain degree of heterogeneity in the disease histogenesis. The implications of these data are threefold. First, MUM1/IRF4 expression corroborates the notion that PEL originates from post-germinal centre, preterminally differentiated B-cells. Second, MUM1/IRF4 may help in the differential diagnosis of PEL among other lymphomas involving the serous body cavities. Finally, MUM1/IRF4 may interact with HHV-8/KSHV-encoded interferon regulatory factors (IRFs) and thus contribute to PEL escape from interferon-mediated control of viral infection. [ABSTRACT FROM AUTHOR]

Explains the role of cytokines in the pathogenesis and management of AIDS-related lymphomas. Pleiotropic effects of interleukin-10; Function of interleukin-7 in B cell proliferation and differentiation; Involvement of interleukin-6 in B cell differentiation; AIDS-related primary effusion of lymphoma; AIDS-related diffuse large cell lymphoma.

AIDS-related non-Hodgkin's lymphomas (AIDS-NHL) are classified into Burkitt's lymphoma, diffuse large cell lymphoma (DLCL), and body cavity based lymphoma. The molecular pathogenesis of AIDS-NHL is complex and involves the genetic alteration of several cancer related genes, including the BCL-6 proto-oncogene. BCL-6 encodes a zinc finger transcription factor which is selectively expressed by germinal center (GC) B-cells, but not by pre-GC or post-GC B-cells. Genetic alterations of BCL-6 occur frequently among B-cell NHL and comprise gross rearrangements as well as small mutations of the 5′ noncoding region of the gene. Gross rearrangements of BCL-6 among AIDS-NHL cluster with 20% AIDS-DLCL. Conversely, mutations of the 5′ noncoding region of BCL-6 occur at sustained frequency throughout the clinico-pathologic spectrum of AIDS-NHL and represent the most common genetic alteration presently detectable in these lymphomas. The frequency of BCL-6 mutations, as well as their location in the proximity of the BCL-6 regulatory regions, suggest that they may play a pathogenetic role in AIDS-related lymphomagenesis. Beside their pathogenetic implications, the occurrence of BCL-6 mutations among AIDS-NHL bears histogenetic relevance because BCL-6 mutations are regarded as a marker of B-cell transition through the GC. Thus, it is conceivable that a large fraction of AIDS-NHL is histogenetically related to GC or post-GC B-cells. This notion is further confirmed by the observation that AIDS-NHL frequently express the BCL-6 protein, which stains selectively GC B-cells throughout B-cell differentiation. [ABSTRACT FROM AUTHOR]

In this study we report on the establishment and characterization of two novel lymphoma cell lines (CRO-AP/3 and CRO-AP/5) which carry infection by human herpesvirus type-8 (HHV-8) and have derived from AIDS-related primary effusion lymphoma (PEL). These two cell lines are representative of different virologic subtypes of PEL, i.e. HHV-8+/EBV- PEL in the case of CRO-AP/3 and HHV-8+/EBV+ PEL in the case of CRO-AP/5. Consistent with the diagnosis of PEL, both CRO-AP/3 and CRO-AP/5 expressed indeterminate (i.e. non-B, non-T) phenotypes although immunogenotypic studies documented their B-cell origin. Both cell lines are devoid of genetic lesions of c-MYC, BCL-2 and p53 as well as gross rearrangements of BCL-6. Detailed histogenetic characterization of these novel PEL cell lines suggests that PEL may derive from a post-germinal centre B cell which has undergone pre-terminal differentiation. The CRO-AP/3 and CRO-AP/5 cell lines may provide a valuable model for clarifying the pathogenesis of PEL. In particular, these cell lines may help understand the relative contribution of HHV-8 and EBV to PEL growth and development and may facilitate the identification of recurrent cytogenetic abnormalities highlighting putative novel cancer related loci relevant to PEL. [ABSTRACT FROM AUTHOR]

Splenic marginal zone lymphoma (SMZL) is one of the few B-cell lymphoma types that remain orphan of molecular lesions in cancer-related genes. Detection of active NF-κB signaling in 14 (58%) of 24 SMZLs prompted the investigation of NF-κB molecular alterations in 101 SMZLs. Mutations and copy number abnormalities of NF-κB genes occurred in 36 (36%) of 101 SMZLs and targeted both canonical (TNFAIP3 and IKBKB) and noncanonical (BIRC3, TRAF3, MAP3K14) NF-κB pathways. Most alterations were mutually exclusive, documenting the existence of multiple independent mechanisms affecting NF-κB in SMZL. BIRC3 inactivation in SMZL recurred because of somatic mutations that disrupted the same RING domain that in extranodal marginal zone lymphoma is removed by the t(11;18) translocation, which points to BIRC3 disruption as a common mechanism across marginal zone B-cell lymphomagenesis. Genetic lesions of NF-κB provide a molecular basis for the pathogenesis of more than 30% of SMZLs and offer a suitable target for NF-κB therapeutic approaches in this lymphoma. [ABSTRACT FROM AUTHOR]