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Sobolewski et al. [J. Appl. Phys. 102, 113302 (2007)] obtained the complex responses of electron density to the long-pulsed RF bias and proposed the gas composition effect as a key underlying factor. In this Comment, the consistent explanations on the complex responses indicate that the ignored slow wall heating should be taken into account. [ABSTRACT FROM AUTHOR]

Voltage and current measured from radio frequency (RF) capacitively coupled plasmas (CCPs) are basic data, from which various powers and impedances are subsequently calculated via fast Fourier transform to gain deep insight into RF CCPs. The specific values of these parameters depend on the nonlinearity of RF CCPs and the interaction with the external circuit, but the relation between harmonic powers and that among the fundamental resistances are not known. These questions are investigated via Multisim software by simplifying the symmetric RF CCP with the nonlinear circuit consisting of a linear resistor and a nonlinear capacitor. The results show that the calculated total RF power is accurately equal to that dissipated by the resistor in discharge. However, it is not true for the fundamental power and harmonic one. The fundamental resistance calculated at the external electrode, which was previously proposed as the plasma resistance, is higher than the latter. The conversion between the fundamental and harmonic powers in the nonlinear ideal capacitor of RF CCPs is the origin of the obtained abnormal feature. In comparison, the plasma resistance calculated from the total RF power and current is unaffected by harmonics and is, thus, more credible, despite that this method requires an assumption of constant transient plasma resistance. [ABSTRACT FROM AUTHOR]

Side discharges as well as filament clusters in atmospheric pressure pulsed radio-frequency dielectric barrier discharges were manipulated by varying the driving frequency, monitored with voltage and current probes, imaged with a slow camera, and quantified by gray-value analysis. Results show that the way of producing a new filament varies with the driving frequency. Based on the side discharge and filament-cluster structure, the key factors influencing the variation are discussed in terms of the electron trapping effect, activation-inhibition effect, and electric field distribution. [ABSTRACT FROM AUTHOR]

Evolutions of distortions in voltage and current waveforms in atmospheric pressure radio frequency (RF) symmetrical alpha-mode discharges were obtained by varying the driving frequency and the length of connection coaxial cable in the external circuit. Based on the fast Fourier transform analysis on waveforms, the pronounced current and voltage waveforms are, respectively, attributed to series and parallel resonances occurring between the atmospheric pressure RF plasma and the external circuit. Despite the weak nonlinearity due to the geometrical symmetry and high collision-frequency at atmospheric pressure, variations of the external circuit such varying the length of the connecting cable can still influence discharges at an equal power. [ABSTRACT FROM AUTHOR]

Kaposi sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV8), is a recent addition to the list of human viruses that are directly associated with lymphoproliferative disorders. KSHV was first shown to be involved in multicentric Castleman disease and primary effusion lymphoma (PEL). Subsequently, the virus was identified in solid lymphomas, often of extranodal sites, with morphological and immunophenotypic characteristics similar to those of PEL, and in other lymphoproliferative disorders with heterogeneous clinicopathological presentations. The recent advances in our understanding of the histology, immunophenotype and pathogenesis of these KSHV-associated lymphoproliferative disorders are reviewed. [ABSTRACT FROM AUTHOR]

The article presents information on the presence of mucosa associated lymphoid tissue (MALT) lymphomas in the stomach and its treatment. A low grade gastric MALT lymphoma appears as a diffuse spread of neoplastic cells from the marginal zone of lymphoid follicles. Histological diagnosis can be very difficult if lymphoid follicles are surrounded by diffusely infiltrating small lymphocytes. Approximately 60% of gastric lymphomas are high grade and are termed as diffuse large B cell lymphomas. Effective H pylon treatment can be very effective in achieving an early response. H pylon treatment is recommended in order to avoid the emergence of antibiotic resistant strains which can be hard to eradicate.

With the introduction of next-generation sequencing, the genetic landscape of the complex group of B-cell lymphoid malignancies has rapidly been unravelled in recent years. This has provided important information about recurrent genetic events and identified key pathways deregulated in each lymphoma subtype. In parallel, there has been intense search and development of novel types of targeted therapy that 'hit' central mechanisms in lymphoma pathobiology, such as BTK, PI3K or BCL2 inhibitors. In this review, we will outline the current view of the genetic landscape of selected entities: follicular lymphoma, diffuse large B-cell lymphoma, mantle cell lymphoma, chronic lymphocytic leukaemia and marginal zone lymphoma. We will detail recurrent alterations affecting important signalling pathways, that is the B-cell receptor/NF-κB pathway, NOTCH signalling, JAK-STAT signalling, p53/DNA damage response, apoptosis and cell cycle regulation, as well as other perhaps unexpected cellular processes, such as immune regulation, cell migration, epigenetic regulation and RNA processing. Whilst many of these pathways/processes are commonly altered in different lymphoid tumors, albeit at varying frequencies, others are preferentially targeted in selected B-cell malignancies. Some of these genetic lesions are either involved in disease ontogeny or linked to the evolution of each disease and/or specific clinicobiological features, and some of them have been demonstrated to have prognostic and even predictive impact. Future work is especially needed to understand the therapy-resistant disease, particularly in patients treated with targeted therapy, and to identify novel targets and therapeutic strategies in order to realize true precision medicine in this clinically heterogeneous patient group. [ABSTRACT FROM AUTHOR]

Aims: Clonality analysis using polymerase chain reaction (PCR) amplification of the immunoglobulin heavy chain (IgH) gene is an important aid to the diagnosis of B cell lymphoproliferative diseases. However, the method has a relatively high false negative rote. In an attempt to improve detection rates simple PCR strategies for clonality andlysis of B cell populations using amplification of Ig light chain genes have been developed. Methods: Novel PCR protocols, designed to amplify Igλ and lgA light chain genes, were evaluated using high molecular weight DNA samples from 28 selected cases of B cell lymphoma with known light chain expression and 12 reactive lymphoid specimens. Products were run on 10% polyacrylamide minigels using heteroduplex analysis. Conventional lgH PCR analysis was also performed. Twelve randomly selected formalin fixed, paraffin wax processed samples from cases submitted for molecular genetic analysis were also studied. Results: Polyclonal products were seen in all reactive lymphoid samples. Using 19K PCR, 24 of 28 lymphomas, including four of five lgH negative cases, displayed monoclonal patterns. Using lgλ PCR, eight of 12 lgλ expressing tumours, including two of five IgH negative cases, showed monoclonal patterns. Standard IgH PCR demonstrated monoclonality in 23 of 28 B cell lymphomas. The detection rate was improved to 27 of 28 lymphomas using heavy and light chain PCR. Efficient amplification was achieved using paraffin wax processed samples, seven of which showed monoclonality compared with eight using IgH PCR. Conclusions: lg light chain PCR, used in conjunction with heavy chain analysis, enables improved detection of B cell monoclonality using routine histological specimens and can provide additional clone specific markers for the study of the biology of B cell tumours. [ABSTRACT FROM AUTHOR]

The API2-MALT1 fusion oncoprotein is created by the recurrent t(11;18)(q21;q21) chromosomal translocation in mucosa-associated lymphoid tissue (MALT) lymphoma. We identified receptor interacting protein-1 (RIP1) as a novel API2-MALT1-associated protein, and demonstrate that RIP1 is required for API2-MALT1 to stimulate canonical nuclear factor kappa B (NF-κB). API2-MALT1 promotes ubiquitination of RIP1 at lysine (K) 377, which is necessary for full NF-κB activation. Furthermore, we found that TNF receptor-associated factor 2 (TRAF2) recruitment is required for API2-MALT1 to induce RIP1 ubiquitination, NF-κB activation and cellular transformation. Although both TRAF2 and RIP1 interact with the API2 moiety of API2-MALT1, this moiety alone is insufficient to induce RIP1 ubiquitination or activate NF-κB, indicating that API2-MALT1-dependent RIP1 ubiquitination represents a gain of function requiring the concerted actions of both the API2 and MALT1 moieties of the fusion. Intriguingly, constitutive RIP1 ubiquitination was recently demonstrated in several solid tumors, and now our study implicates RIP1 ubiquitination as a critical component of API2-MALT1-dependent lymphomagenesis. [ABSTRACT FROM AUTHOR]

Mucosa-associated lymphoid tissue (MALT) lymphoma is characterized by t(11;18)(q21;q21)/API2-MALT1, t(1;14)(p22;q32)/BCL10-IGH and t(14;18)(q32;q21)/IGH-MALT1, which commonly activate the nuclear factor (NF)-κB pathway. Gastric MALT lymphomas harboring such translocations usually do not respond to Helicobacter pylori eradication, while most of those without translocation can be cured by antibiotics. To understand the molecular mechanism of these different MALT lymphoma subgroups, we performed gene expression profiling analysis of 21 MALT lymphomas (13 translocation-positive, 8 translocation-negative). Gene set enrichment analysis (GSEA) of the NF-κB target genes and 4394 additional gene sets covering various cellular pathways, biological processes and molecular functions have shown that translocation-positive MALT lymphomas are characterized by an enhanced expression of NF-κB target genes, particularly toll like receptor (TLR)6, chemokine, CC motif, receptor (CCR)2, cluster of differentiation (CD)69 and B-cell CLL/lymphoma (BCL)2, while translocation-negative cases were featured by active inflammatory and immune responses, such as interleukin-8, CD86, CD28 and inducible T-cell costimulator (ICOS). Separate analyses of the genes differentially expressed between translocation-positive and -negative cases and measurement of gene ontology term in these differentially expressed genes by hypergeometric test reinforced the above findings by GSEA. Finally, expression of TLR6, in the presence of TLR2, enhanced both API2-MALT1 and BCL10-mediated NF-κB activation in vitro. Our findings provide novel insights into the molecular mechanism of MALT lymphomas with and without translocation, potentially explaining their different clinical behaviors. [ABSTRACT FROM AUTHOR]

A letter to the editor regarding the article "A20 is targeted by promoter methylation, deletion and inactivating mutation in MALT lymphoma," published in a previous issue is presented.

Aims:  To elucidate the clinicopathological features and prognostic factors of primary intestinal diffuse large B-cell lymphoma (PI-DLBL). Methods and results:  Archival tissues from 30 tumours were used for tissue microarray construction, immunohistochemistry and interphase fluorescence in situ hybridization for chromosomal translocation. The M:F ratio was 1.7:1, with a median age of 60 years. The ileum and ileocaecum were most frequently involved (40% each). Fourteen (47%) were at stage IE disease, 15 (50%) at stage IIE. Five (17%) tumours were perforated at presentation. The tumours expressed Bcl-6 (73%), MUM1 (70%), Bcl-2 (67%) and CD10 (23%). Nine (30%) were classified as germinal centre B-cell (GCB) phenotype and 21 non-GCB. Eight of 30 (27%), 7/30 (23%) and 2/29 (7%) cases were positive for rearrangements involving IGH, BCL6, and C-MYC loci, respectively, whereas all cases were negative for BCL2 and CCND1 translocation. Perforation was a poor prognostic indicator, with a hazard ratio of tumour-related death at 8.75 ( P = 0.001). The differentiation antigens, GCB versus non-GCB phenotype, or lymphoma-associated translocations were of no prognostic significance. Conclusions:  We found a higher rate of perforation and lower frequency of GCB phenotype in PI-DLBL in Taiwan compared with other geographical areas; perforation is a poor prognostic indicator. [ABSTRACT FROM AUTHOR]

Aims: Morphological, immunophenotypic and genetic heterogeneity amongst mantle cell lymphomas (MCLs) can lead to difficulties in diagnosis and management. The aim was to describe the clinical and pathological features of MCLs with aberrant expression of CD10. Methods and results: Of 17 specimens from 13 patients, 14 expressed CD10 and three (presenting before or after a CD10+ specimen) did not. All expressed cyclin D1 and carried the t(11;14)(q13;q32)/ CCND1-IGH translocation. Similar to non-selected MCL patients, most patients had disseminated disease and an adverse clinical course. Five specimens showed pleomorphic blastoid morphology and blastoid transformation was associated with a change in phenotype, including gain or loss of CD10. Additional phenotypic variations likely to cause diagnostic difficulty were present in eight specimens: five were CD5− and five (all CD10+) expressed Bcl-6. One Bcl-6+ case carried a BCL-6 translocation and three others had extra copies of the BCL-6 gene. Sequence analysis of the immunoglobulin heavy chain variable region in five cases showed only one to have low-level somatic mutation, indicating that they did not arise from germinal centre B cells. Conclusions: Expression of CD10 by MCL is often associated with other variant morphological, immunophenotypic or genetic features, but does not reflect derivation from germinal centre B cells. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented that discusses the cyclin D1-positive diffuse large B-cell lymphoma.

A letter to the editor about mucosa-associated lymphoid tissue (MALT) lymphoma is presented.

Aims: To characterize the clinicopathological features of sporadic Burkitt lymphoma (BL). Methods and results: A retrospective study of 17 paediatric and 14 adult BLs with history and histopathology review, immunohistochemistry, Epstein–Barr virus (EBV) in situ hybridization (EBER) and fluorescence in situ hybridization. There was no statistically significant difference in gender, frequency of central nervous system (CNS) involvement and leukaemic change at presentation, or frequency of CD10+/Bcl-2−/Bcl-6+ (88% versus 86%), Ki67 labelling index, EBER (24% versus 21%), or C-MYC translocation (100% versus 92%) between paediatric and adult tumours. Correct pretreatment diagnoses were made in 13/17 (76%) paediatric and in 9/14 (64%) adult tumours. Twenty-eight patients received chemotherapy including 13/16 (81%) paediatric and 3/12 (25%) adult patients with appropriate regimens; 16 (57%) received CNS prophylaxis. The 1- and 5-year overall survival (OS) rates for paediatric patients were 80% and 50%, respectively, whereas 1-year OS for adults was 15%. Conclusions: Sporadic paediatric and adult BLs were phenotypically and genotypically similar. The significant prognosticators were age ( P = 0.001), with or without CNS prophylaxis ( P = 0.004), and CNS involvement ( P = 0.008) and leukaemic change ( P = 0.019) in disease course. The poor outcome in adult patients might be related to incorrect diagnosis and inappropriate treatment. [ABSTRACT FROM AUTHOR]

Aims: To identify distinguishing histological, immunophenotypic and molecular genetic features between angioimmunoblastic T-cell lymphoma (AITL) and peripheral T-cell lymphoma (PTL). Methods: Nodal T-cell lymphomas examined ( n =137), included AITL ( n = 89), PTL ( n = 22), anaplastic large cell lymphoma ( n = 16) and ‘AITL/PTL indeterminate’ ( n = 10) with overlapping features between AITL and PTL, showing morphology typical of AITL but lacking follicular dendritic cell expansion. Immunohistochemistry for CD3, CD20, CD21 and CD10, in situ hybridization for Epstein–Barr virus encoded RNA (EBER) and polymerase chain reaction for T-cell and B-cell clonality analysis were performed. Results: Of the AITLs, 74/89 showed typical morphology, whereas 15/89 showed hyperplastic follicles. AITL and ‘AITL/PTL indeterminate’ showed a polymorphous infiltrate and prominent vascularity in all cases. In both groups, CD10 was present in the majority and clear cells and EBER positivity were specific (but not universal) features lacking in PTL. Detection of T-cell clonality was significantly higher in AITL (90%) compared with PTLu (59%). Conclusion: Clear cells and EBV infection (when present) are useful distinguishing features and CD10 a sensitive and specific marker of AITL. Hyperplastic follicles are present in a significant minority of AITL. AITL/PTL indeterminate probably falls within the spectrum of AITL rather than PTL. [ABSTRACT FROM AUTHOR]

Chlamydia pneumoniae, Chlamydia trachomatis and Chlamydia psittaci were detected at low frequencies (<20%) among 69 pulmonary mucosa-associated lymphoid tissue (MALT) lymphomas, 30 other lymphoproliferative disorders (LPD) and 44 non-LPD. The incidence of individual Chlamydiae was generally higher in MALT lymphoma than non-LPD, although not reaching statistical significance. Mycoplasma pneumoniae DNA was not detected.British Journal of Cancer (2007) 97, 949–951. doi:10.1038/sj.bjc.6603981 www.bjcancer.com Published online 18 September 2007 [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to an article related to gastric mucosa associated lymphoid tissue lymphomas that do not respond to Hpylori eradication, which was published in a previous issue.

A correction to the article "A20 is targeted by promoter methylation, deletion and inactivating mutation in MALT lymphoma," published in a previous issue is presented.

Presents a letter to the editor regarding a case of primary urethral malt lymphoma with high proliferation fraction.

Objective An aberrant immunophenotype and monoclonality of intraepithelial lymphocytes (IELs) are frequently found in refractory coeliac disease (RCD). However, the utility of continual monitoring of IEL immunophenotype and clonality in the surveillance of RCD remains to be studied. Design The diagnostic and follow-up biopsies from 33 patients with CD, 7 with suspected RCD, 41 with RCD and 20 with enteropathy-associated T cell lymphoma (EATL) (including 11 evolved from RCD) were investigated by CD3ϵ/CD8 double immunohistochemistry and PCR-based clonality analysis of the rearranged T cell receptor (TCR) genes. Results An aberrant immunophenotype (CD3ϵ+CD8- IELs ≥40%) and monoclonality were detected occasionally in CD biopsies, either transiently in patients with CD not compliant with a gluten-free diet or in those who subsequently developed suspected RCD, RCD or EATL. In contrast, the aberrant immunophenotype and monoclonality were found in 30 of 41 (73%) and 24 of 37 (65%) biopsies, respectively, at the time of RCD diagnosis. Among the patients with RCD who did not show these abnormalities in their diagnostic biopsies, 8 of 10 (80%) and 5 of 11 (45%) cases gained an aberrant immunophenotype and monoclonality, respectively, during follow-up. Irrespective of whether detected in diagnostic or follow-up biopsies, persistence of both abnormalities was characteristic of RCD. Importantly, the presence of concurrent persistent monoclonality and aberrant immunophenotype, especially ≥80% CD3ϵ+CD8- IELs, was a strong predictor of EATL development in patients with RCD (p=0.001). Conclusions Continual monitoring of both immunophenotype and clonality of IELs is more important than snapshot analysis for RCD diagnosis and follow-up, and could provide a useful tool for surveillance of patients at risk of EATL. [ABSTRACT FROM AUTHOR]