Lymphoma is the most common malignancy arising in the ocular adnexa, which includes conjunctiva, lachrymal gland, lachrymal sac, eyelids, orbit soft tissue, and extraocular muscles. Ocular adnexal lymphoma (OAL) accounts for 1%–2% of non-Hodgkin lymphoma and 5%–15% of extranodal lymphoma. The most common and well-studied histotype is represented by marginal zone B-cell lymphoma. This review covers the prevalence, clinical presentation, behavior, and histological and molecular features of uncommon forms of primary OAL and provides practical recommendations for therapeutic management.
Lymphoma is the most common malignancy arising in the ocular adnexa, which includes conjunctiva, lachrymal gland, lachrymal sac, eyelids, orbit soft tissue, and extraocular muscles. Ocular adnexal lymphoma (OAL) accounts for 1%–2% of non-Hodgkin lymphoma and 5%–15% of extranodal lymphoma. Histology, stage, and primary localizations are the most important variables influencing the natural history and therapeutic outcome of these malignancies. Among the various lymphoma variants that could arise in the ocular adnexa, marginal zone B-cell lymphoma (OA-MZL) is the most common one. Other types of lymphoma arise much more rarely in these anatomical sites; follicular lymphoma is the second most frequent histology, followed by diffuse large B-cell lymphoma and mantle cell lymphoma. Additional lymphoma entities, like T-cell/natural killer cell lymphomas and Burkitt lymphoma, only occasionally involve orbital structures. Because they are so rare, related literature mostly consists of anecdotal cases included within series focused on OA-MZL and sporadic case reports. This bias hampers a global approach to clinical and molecular properties of these types of lymphoma, with a low level of evidence supporting therapeutic options. This review covers the prevalence, clinical presentation, behavior, and histological and molecular features of uncommon forms of primary OAL and provides practical recommendations for therapeutic management.
Ocular adnexal lymphoma; Diffuse large B-cell lymphoma; Follicular lymphoma; Mantle cell lymphoma; T-cell lymphoma
Ocular adnexal lymphomas (OAL) involve the peri-global soft tissues like orbit, eyelid, conjunctiva, lacrimal gland. We describe a rare case of primary bilateral OAL, histomorphologically small lymphocytic lymphoma, B cell phenotype of lacrimal gland origin. Rapid intraoperative diagnosis can be suggested on imprint cytology; subsequent histology and immunohistochemistry are helpful for confirmation and further line of management. Since no preformed lymphoid structures are expected within the orbit or lacrimal gland, any lymphoid mass here should be critically evaluated as a lymphoproliferative lesion.
Lymphoma; Lacrimal; Ocular adnexal; B cell; Bilateral; Imprint cytology
The LOU/C/Jall (LOU) rat strain is considered a model of healthy aging due to its increased longevity, maintenance of stable body weight (BW) throughout life and low incidence of age-related diseases. However, aging LOU rat cognitive and anxiety status has yet to be investigated. In the present study, male and female LOU rat cognitive performances (6–42 months) were assessed using novel object recognition and Morris Water Maze tasks. Recognition memory remained intact in all LOU rats up to 42 months of age. As for spatial memory, old LOU rat performed similarly as young animals for learning acquisition, reversal learning, and retention. While LOU rat BW remained stable despite aging, 20-month-old ad-libitum-fed (OAL) male Sprague Dawley rats become obese. We determined if long-term caloric restriction (LTCR) prevents age-related BW increase and cognitive deficits in this rat strain, as observed in the obesity-resistant LOU rats. Compared to young animals, recognition memory was impaired in OAL but intact in 20-month-old calorie-restricted (OCR) rats. Similarly, OAL spatial learning acquisition was impaired but LTCR prevented the deficits. Exacerbated stress responses may favor age-related cognitive decline. In the elevated plus maze and open field tasks, LOU and OCR rats exhibited high levels of exploratory activity whereas OAL rats displayed anxious behaviors. Expression of prodynorphin (Pdyn), an endogenous peptide involved in stress-related memory impairments, was increased in the hippocampus of OAL rats. Group 1 metabotropic glutamate receptor 5 and immediate early genes Homer 1a and Arc expression, both associated with successful cognitive aging, were unaltered in aging LOU rats but lower in OAL than OCR rats. Altogether, our results, supported by principal component analysis and correlation matrix, suggest that intact memory and low anxiety are associated with glutamatergic signaling and low Pdyn expression in the hippocampus of non-obese aging rats.
aging; cognition; anxiety; caloric restriction; obesity; glutamate receptors
Diffuse large B-cell lymphoma (DLBCL), the most common form of lymphoma in adulthood, comprises multiple biologically and clinically distinct subtypes including germinal center B cell-like (GCB) and activated B cell-like (ABC) DLBCL1. Gene expression profile studies have shown that its most aggressive subtype, ABC-DLBCL, is associated with constitutive activation of the NF-kB transcription complex2. However, except for a small fraction of cases3, it remains unclear whether NF-kB activation in these tumors represents an intrinsic program of the tumor cell of origin or a pathogenetic event. Here we show that >50% of ABC-DLBCL and a smaller fraction of GCB-DLBCL carry somatic mutations in multiple genes, including negative (TNFAIP3/A20) and positive (CARD11, TRAF2, TRAF5, MAP3K7/TAK1 and TNFRSF11A/RANK) regulators of NF-kB. Of these, the A20 gene, which encodes for a ubiquitin-modifying enzyme involved in termination of NF-kB responses, is most commonly affected, with ~30% of patients displaying biallelic inactivation by mutations and/or deletions. When reintroduced in cell lines carrying biallelic inactivation of the gene, A20 induced apoptosis and cell growth arrest, indicating a tumor suppressor role. Less frequently, missense mutations of TRAF2 and CARD11 produce molecules with significantly enhanced ability to activate NF-kB. Thus, our results demonstrate that NF-kB activation in DLBCL is caused by genetic lesions affecting multiple genes, whose loss or activation may promote lymphomagenesis by leading to abnormally prolonged NF-kB responses.
Lymphoplasmacytic lymphomas and marginal zone lymphomas of nodal, extra-nodal and splenic types account for 10% of non-Hodgkin lymphomas. They are similar at the cell differentiation level, sometimes making difficult to distinguish them from other indolent non-Hodgkin lymphomas. To better characterize their genetic basis, we performed array-based comparative genomic hybridization in 101 marginal zone lymphomas (46 MALT, 35 splenic and 20 nodal marginal zone lymphomas) and 13 lymphoplasmacytic lymphomas. Overall, 90.1% exhibited copy-number abnormalities. Lymphoplasmacytic lymphomas demonstrated the most complex karyotype (median=7 copy-number abnormalities), followed by MALT (4), nodal (3.5) and splenic marginal zone lymphomas (3). A comparative analysis exposed a group of copy-number abnormalities shared by several or all the entities with few disease-specific abnormalities. Gain of chromosomes 3, 12 and 18 and loss of 6q23–q24 (TNFAIP3) were identified in all entities. Losses of 13q14.3 (MIRN15A-MIRN16-1) and 17p13.3-p12 (TP53) were found in lymphoplasmacytic and splenic marginal zone lymphomas; loss of 11q21–q22 (ATM) in nodal, splenic marginal zone and lymphoplasmacytic lymphomas; loss of 7q32.1–q33 in MALT, splenic and lymphoplasmacytic lymphomas. Abnormalities affecting the NF-kB pathway were observed in 70% of MALT and lymphoplasmacytic lymphomas and 30% of splenic and nodal marginal zone lymphomas, suggesting distinct roles of this pathway in the pathogenesis/progression of these subtypes. Elucidation of the genetic alterations contributing to the pathogenesis of these lymphomas may guide to design specific therapeutic approaches.
MZL; LPL; aCGH; copy-number abnormalities; NF-kB pathway
AIMS—To correlate histological features of ocular adnexal lymphoma using the revised European American lymphoma classification (REAL), with stage of disease at presentation, treatment modalities, and patient outcome. MALT lymphoma defines an extranodal marginal zone B cell lymphoma as outlined in the REAL classification. Comparison groups of patients included those with primary ocular adnexal MALT lymphoma versus primary ocular adnexal lymphomas of other types, MALT lymphoma versus non-MALT lymphomas (primary and secondary), and primary ocular adnexal lymphoma (MALT lymphomas and other types) versus secondary ocular adnexal lymphomas.
METHODS—A retrospective review of the National Ophthalmic Pathology Laboratory records identified 20 cases of ocular adnexal lymphoma over a 10 year period which were reclassified using appropriate immunohistochemical stains. Patients' medical records were examined for data including stage of the disease at presentation, mode of treatment, and patient outcome.
RESULTS—Among the 20 cases identified 14 had primary ocular adnexal lymphomas. 10 of the primary lymphomas had histological features of MALT lymphoma. One case was a primary ocular adnexal T cell lymphoma, one a follicular centre, follicular B cell lymphoma, and two were large cell B cell lymphomas. Six cases had systemic disease, four large B cell, one follicular centre, follicular B cell, and one mantle cell. A significantly higher proportion of patients with MALT lymphomas had early disease (p = 0.005), initially required local treatment (p = 0.005) and were alive at last follow up (p = 0.001) than those without. Two patients with MALT lymphoma had recurrence of lymphoma which responded to further treatment.
CONCLUSIONS—Patients with primary ocular adnexal MALT lymphomas present with localised disease requiring local treatment and have a better outcome compared with patients with other types. As a small percentage of these tumours recur, patients should be followed up indefinitely.
The etiology and pathogenesis of ocular adnexal extranodal marginal zone lymphoma (OAEMZL) are still unknown and the association with Chlamydophila psittaci (C. psittaci) has been shown in only some geographic regions. Herein we comprehensively examined the frequency of chromosomal translocations as well as CARD11, MYD88 (L265P) and A20 mutations /deletions in 45 C. psittaci negative OAEMZLs. t(14;18)(q32;q21) IGH-MALT1 and t(11;18)(q21;q21) API2-MALT1 were not detected in any of the analyzed tumors while 3 tumors harbored IGH translocations to an unidentified partner. CARD11 mutations were not found in all the analyzed tumors while MYD88 L265P mutation was detected in 3 (6.7%) tumors. A20 mutations and deletions were each detected in 7(15.6%) and 6(13.3%) of the tumors, respectively. Therefore, the observed genetic aberrations could account for the activation of NF-kB signaling pathway in only a minority of the cases. Further studies are needed to identify the molecular mechanisms underlying the pathogenesis of OAEMZL.
MALT lymphoma; ocular adnexa; translocations; mutations; NF-kB
Extranodal marginal zone lymphomas of mucosa associated lymphoid tissue type (MALT lymphomas) develop from acquired reactive infiltrates directed against external or auto-antigens. Although some European cases of ocular adnexal MALT lymphoma have been associated with Chlamydia psittaci infections, C. psittaci has not been detected in large studies of U.S. based cases. To evaluate whether the growth of U.S. based ocular adnexal MALT lymphomas may be promoted by a similar antigen, the expressed immunoglobulin VH genes were identified and analyzed in 10 cases. Interestingly, the VH genes in 2 cases used the same VH1 family V1-2 gene segment, and 3 cases used the same VH4 family V4-34 gene segment. The other five cases all used different gene segments V4-31, V5-51, V3-23, V3-30, and V3-7. All of the VH genes were mutated from germline, with percent homologies ranging between 96.9% to 89.0%. The distribution of replacement and silent mutations within the VH genes was non-random consistent with the maintenance of immunoglobulin function and also strongly suggestive of antigen selection in the 6 VH genes with highest mutation loads. The CDR3 sequences in 2 of 3 VH-34 cases were the same size (15 amino acids), and had similar sizes in the 2 VH1-2 cases (18 & 16 amino acids). In conclusion, U.S. based MALT lymphomas of the ocular adnexa preferentially express a limited set of VH gene segments not frequently used by other MALT lymphomas and consistent with some recognizing similar antigens. Analysis of somatic mutations present within the VH genes is also consistent with antigen binding stimulating the growth of these lymphomas.
MALT lymphoma; ocular adnexa; immunoglobulin VH gene
Marine microbes use alginate lyases to degrade and catabolize alginate, a major cell wall matrix polysaccharide of brown seaweeds. Microbes frequently contain multiple, apparently redundant alginate lyases, raising the question of whether these enzymes have complementary functions. We report here on the molecular cloning and functional characterization of three exo-type oligoalginate lyases (OalA, OalB, and OalC) from Vibrio splendidus 12B01 (12B01), a marine bacterioplankton species. OalA was most active at 16°C, had a pH optimum of 6.5, and displayed activities toward poly-β-d-mannuronate [poly(M)] and poly-α-l-guluronate [poly(G)], indicating that it is a bifunctional enzyme. OalB and OalC were most active at 30 and 35°C, had pH optima of 7.0 and 7.5, and degraded poly(M·G) and poly(M), respectively. Detailed kinetic analyses of oligoalginate lyases with poly(G), poly(M), and poly(M·G) and sodium alginate as substrates demonstrated that OalA and OalC preferred poly(M), whereas OalB preferred poly(M·G). The catalytic efficiency (kcat/Km) of OalA against poly(M) increased with decreasing size of the substrate. OalA showed kcat/Km from 2,130 mg−1 ml s−1 for the trisaccharide to 224 mg−1 ml s−1 for larger oligomers of ∼50 residues, and 50.5 mg−1 ml s−1 for high-molecular-weight alginate. Although OalA was most active on the trisaccharide, OalB and OalC preferred dimers. Taken together, our results indicate that these three Oals have complementary substrate scopes and temperature and pH adaptations.
Loss of c-IAP2 ubiquitin ligase activity, which occurs in the lymphoma-causing c-IAP2/MALT1 fusion protein, activates non-canonical NF-κB signaling and results in B cell abnormalities characteristic of MALT lymphoma.
Chromosomal translocations between loci encoding MALT1 and c-IAP2 are common in MALT lymphomas. The resulting fusion proteins lack the c-IAP2 RING domain, the region responsible for its ubiquitin protein ligase (E3) activity. Ectopic expression of the fusion protein activates the canonical NF-κB signaling cascade, but how it does so is controversial and how it promotes MALT lymphoma is unknown. Considering recent reports implicating c-IAP1 and c-IAP2 E3 activity in repression of non-canonical NF-κB signaling, we asked if the c-IAP2/MALT fusion protein can initiate non-canonical NF-κB activation. Here we show that in addition to canonical activation, the fusion protein stabilizes NIK and activates non-canonical NF-κB. Canonical but not non-canonical activation depended on MALT1 paracaspase activity, and expression of E3-inactive c-IAP2 activated non-canonical NF-κB. Mice in which endogenous c-IAP2 was replaced with an E3-inactive mutant accumulated abnormal B cells with elevated non-canonical NF-κB and had increased numbers of B cells with a marginal zone phenotype, gut-associated lymphoid hyperplasia, and other features of MALT lymphoma. Thus, the c-IAP2/MALT1 fusion protein activates NF-κB by two distinct mechanisms, and loss of c-IAP2 E3 activity in vivo is sufficient to induce abnormalities common to MALT lymphoma.
MALT (mucosal associated lymphoid tissue) lymphomas commonly express a mutant protein that contains a portion of the ubiquitin protein ligase cellular Inhibitor of Apoptosis 2 (c-IAP2) and a portion of the paracaspase MALT1. Expression of this fusion protein activates the anti-apoptotic transcription factor NF-κB, but how it does so and whether or not this activity contributes to lymphomagenesis is not known. Here we identify the mechanisms by which the fusion protein activates NF-κB and show that absence of c-IAP2 ubiquitin protein ligase activity in mice, as is the case in patients that express the fusion protein, results in spontaneous activation of NF-κB and many of the phenotypic cellular features of MALT lymphoma. Our findings demonstrate that c-IAP2 ubiquitin protein ligase activity dampens constitutive NF-κB activity and maintains B cell homeostasis, and provide genetic evidence that the loss of this enzymatic activity in the fusion protein has a major contributing role in MALT lymphomagenesis.
Ocular adnexa MALT-lymphomas represent approximatively 5-15% of all extranodal lymphomas. Almost 75% of OAMLs are localized in orbital fat, while 25% of cases involves conjunctive. MALT-lymphomas often recognize specific environmental factors responsible of lymphoma development and progression. In particular as Helicobacter pylori in gastric MALT lymphomas, other bacterial infections have been recognized related to MALT lymphomas in specific site. Recently Chlamydia psittaci has been identified in Ocular Adnexa MALT lymphomas, with variable frequence dependently from geographic areas. Thus bacterial infection is responsible of clonal selection on induced MALT with subsequent lymphoma development. Moreover Chlamydia psittaci could promote chromosomal aberration either through genetic instability as a consequence of induced proliferation and probably through DNA oxidative damage. The most common translocation described in MALT lymphomas affects NF-kB pathway with a substantial antiapoptotic effect. Several therapeutic approaches are now available, but the use of antibiotic-therapy in specific cases, although with conflicting results, could improve the treatment of ocular adnexa MALT lymphomas. In this review we analyse the most relevant features of Ocular adnexa MALT lymphomas, underlining specific biological characteristics mainly related to the potential role of Chlamydia psittaci in lymphomagenesis.
Chlamydia psittaci; Ocular Adnexa; MALT lymphoma; t(14;18); bcl10
Elevations in systemic free fatty acids (FFA) contribute to insulin resistance. To determine the effects of an acute elevation in FFA on insulin action with aging, we infused saline or intralipid (IL) during a hyperinsulinemic–euglycemic clamp in three groups of rats: young ad libitum–fed (YAL), old ad libitum–fed (OAL), and old on lifelong calorie restriction (OCR). The OCR group was included to distinguish between aging per se and age-related changes in body fat distribution. IL induced marked insulin resistance in both YAL and OCR, but the onset of insulin resistance was approximately two to three times more rapid in OCR as compared with YAL. In response to IL infusion, plasminogen-activating inhibitor-1 (PAI-1) expression was increased in subcutaneous fat from OAL animals. In visceral fat, a marked increase in PAI-1 and interleukin-6 expression was observed in OAL and OCR rats, but not YAL, in response to IL treatment. Thus, aging per se increases the inflammatory response to excess nutrients and vulnerability to FFA-induced insulin resistance with aging.
Aging; Calorie restriction; Lipids; Insulin resistance; Adipokines
Proliferation and survival of Hodgkin and Reed/Sternberg (HRS) cells, the malignant cells of classical Hodgkin lymphoma (cHL), are dependent on constitutive activation of nuclear factor κB (NF-κB). NF-κB activation through various stimuli is negatively regulated by the zinc finger protein A20. To determine whether A20 contributes to the pathogenesis of cHL, we sequenced TNFAIP3, encoding A20, in HL cell lines and laser-microdissected HRS cells from cHL biopsies. We detected somatic mutations in 16 out of 36 cHLs (44%), including missense mutations in 2 out of 16 Epstein-Barr virus–positive (EBV+) cHLs and a missense mutation, nonsense mutations, and frameshift-causing insertions or deletions in 14 out of 20 EBV− cHLs. In most mutated cases, both TNFAIP3 alleles were inactivated, including frequent chromosomal deletions of TNFAIP3. Reconstitution of wild-type TNFAIP3 in A20-deficient cHL cell lines revealed a significant decrease in transcripts of selected NF-κB target genes and caused cytotoxicity. Extending the mutation analysis to primary mediastinal B cell lymphoma (PMBL), another lymphoma with constitutive NF-κB activity, revealed destructive mutations in 5 out of 14 PMBLs (36%). This report identifies TNFAIP3 (A20), a key regulator of NF-κB activity, as a novel tumor suppressor gene in cHL and PMBL. The significantly higher frequency of TNFAIP3 mutations in EBV− than EBV+ cHL suggests complementing functions of TNFAIP3 inactivation and EBV infection in cHL pathogenesis.
Ocular lymphomas can be divided into intraocular lymphomas and ocular adnexal lymphomas. The vitreoretinal lymphoma—usually a diffuse large B-cell lymphoma (DLBCL) of high-grade malignancy—is the most common lymphoid malignancy arising in the eye, while the extranodal marginal zone B-cell lymphoma (EMZL), an indolent often recurrent tumour, occurs most frequently in the ocular adnexal tissue. The two lymphoma subtypes differ significantly in their clinical presentation, subsequent course and outcome as well as in their underlying morphological, immunophenotypical and genetic features. The molecular processes involved in DLBCL and EMZL development are complex, and include chromosomal translocations, mutations caused by aberrant somatic hypermutation, sporadic somatic mutations, and copy number alterations, characterized by deletions and amplifications. These lead to alterations in particular signalling pathways, which in turn activate transcription factors, such as nuclear factor NF-κB. This review provides an overview of the histological features of DLBCL and EMZL, and discusses the current insights into the molecular mechanisms underlying the development of these tumours, when they occur systemically and particularly when they arise in ocular tissues.
ocular adnexal lymphoma; extranodal marginal zone lymphoma; diffuse large B-cell lymphoma; ABC DLBCL; GCB DLBCL; vitreoretinal lymphoma
Diffuse large B cell lymphoma (DLBCL) comprises specific subtypes, disease entities, and other not otherwise specified (NOS) lymphomas. This review will focus on DLBCL NOS because of their prevalence and their heterogeneity with respect to morphology, clinical presentation, biology, and response to treatment. Gene expression profiling of DLBCL NOS has identified molecular subgroups that correlate with prognosis and may have relevance for treatment based on signaling pathways. New technologies have revealed that the “activated B cell” subgroup is linked to activation of the nuclear factor kB (NF-kB) pathway, with mutations found in CD79A/B, CARD11, and MYD88, and loss of function mutations in TNFAIP3. The “germinal center B cell-like” subgroup is linked to mutational changes in EZH2 and CREBBP. Biomarkers that are related to pathways promoting tumor cell growth and survival in DLBCL have been recognized, although their predictive role requires clinical validation. Immunohistochemistry for detecting the expression of these biomarkers is a practical technique that could provide a rational for clinical trial design.
DLBCL; Biomarkers; Prognosis; Diagnosis; Treatment
To determine if short-term calorie restriction reverses vascular endothelial dysfunction in old mice, old (O, n=30) and young (Y, n=10) male B6D2F1 mice were fed ad libitum (AL) or calorie restricted (CR, ∼30%) for 8 weeks. Ex vivo carotid artery endothelium-dependent dilation (EDD) was impaired in OAL vs. YAL (74±5 vs. 95±2% of maximum dilation, P<0.05), whereas OCR and YCR did not differ (96±1 vs. 94±3%). Impaired EDD in OAL was mediated by reduced nitric oxide (NO) bioavailability associated with decreased endothelial NO synthase expression (aorta) (P<0.05), both of which were restored in OCR. Nitrotyrosine, a cellular marker of oxidant modification, was markedly elevated in OAL (P<0.05), whereas OCR was similar to Y. Aortic superoxide production was 150% greater in OAL vs. YAL (P<0.05), but normalized in OCR, and TEMPOL, a superoxide dismutase (SOD) mimetic that restored EDD in OAL (to 97±2%), had no effect in Y or OCR. OAL had increased expression and activity of the oxidant enzyme, NADPH oxidase, and its inhibition (apocynin) improved EDD, whereas NADPH oxidase in OCR was similar to Y. Manganese SOD activity and sirtuin1 expression were reduced in OAL (P<0.05), but restored to Y in OCR. Inflammatory cytokines were greater in OAL vs. YAL (P<0.05), but unaffected by CR. Carotid artery endothelium-independent dilation did not differ among groups. Short-term CR initiated in old age reverses age-associated vascular endothelial dysfunction by restoring NO bioavailability and reducing oxidation stress via reduced NADPH oxidase-mediated superoxide production and stimulation of anti-oxidant enzyme activity, and upregulates sirtuin1.
During the B-cell response to T-cell-dependent antigens, the B cells undergo a rapid proliferative phase in the germinal centre. This is accompanied by the introduction of mutations into the immunoglobulin (Ig) variable region (V) genes. The B cells are then selected according to the affinity of the encoded immunoglobulin for antigen, resulting in affinity maturation of the response. Analysis of mutations in IgV genes has given insight into the history of individual B cells and their malignancies. In most cases, analysis of mutations confirms classifications of B-cell lineage designated by studies of cellular morphology and surface antigen expression. However, of particular interest is the subdivision of groups of malignancies by analysis of somatic hypermutation. It is now apparent that there are two subsets of chronic lymphocytic leukaemia (CLL), one with a low load of mutations and poor prognosis. and one with a heavy load of mutations with a much more favourable prognosis. In addition, in Burkitt's lymphoma, sporadic and endemic subtypes are now considered possibly to have a different pathogenesis, reflected in differences in the numbers of mutations. Hodgkin's disease, which was a mystery for many years, has now been shown to be a B-cell tumour. Although in many cases the Ig genes are crippled by somatic hypermutation, it is thought that failure to express Ig is more likely to be associated with problems of transcription. It has been proposed that the distribution of mutations in a B-cell lymphoma can be used to determine whether a lymphoma is selected. We have investigated the load and distribution of mutations in one group of lymphomas--marginal zone B-cell lymphomas of mucosa-associated lymphoid tissues (MALT-type lymphoma), which are dependent on Helicobacter pylori for disease progression, to investigate the limits of information that can be derived from such studies. Comparison of the load of mutations demonstrates that these tumours have approximately the same load of mutations as normal mucosal marginal zone B cells from the Peyer's patches and mucosal plasma cells. This is consistent with the origin of these cells from mucosal marginal zone B cells with plasma cell differentiation. To investigate selection in MALT lymphomas we compared a region of the framework region three in ten MALT lymphomas which use the V(H4) family, with the same codons in groups of V(H4) genes that are out of frame between V and J. The latter accumulate mutations but are not used and are not selected. A group of V(H4) genes are in-frame between V and J were also included for comparison. There were no obvious differences in the distribution of mutations between the groups of genes; the same hot spots and cold spots were apparent in each. In the MALT lymphomas, selection was apparent in the framework regions only and the tendency was to conserve. We therefore feel that there is selection to conserve antibody structure and that this does not reflect selection for antigen. We do not believe that antigen selection can be deduced reliably from sequence information alone. It is possible that somatic hypermutation could be a cause of malignancy since it has been shown that the process may generate DNA strand breaks and is known to be able to generate insertions and deletions. Such events may mediate the translocation of genes--a process that is pivotal in the evolution of many lymphomas.
The TNFAIP3 gene, which encodes a ubiquitin-modifying enzyme (A20) involved in the negative regulation of NF-κB signaling, is frequently inactivated by gene deletions/mutations in a variety of B-cell malignancies. However, the detection of this in primary Hodgkin lymphoma (HL) specimens is hampered by the scarcity of Hodgkin Reed-Sternberg (HR-S) cells even after enrichment by micro-dissection.
We used anti-CD30 immunofluorescence with fluorescence in-situ hybridization (FISH) to evaluate the relative number of TNFAIP3/CEP6 double-positive signals in CD30-positive cells.
From a total of 47 primary classical Hodgkin lymphoma (cHL) specimens, 44 were evaluable. We found that the relative numbers of TNFAIP3/CD30 cells were distributed among three groups, corresponding to those having homozygous (11%), heterozygous (32%), and no (57%) deletions in TNFAIP3. This shows that TNFAIP3 deletions could be sensitively detected using our chosen methods.
Comparing the results with mutation analysis, TNFAIP3 inactivation was shown to have escaped detection in many samples with homozygous deletions. This suggests that TNFAIP3 inactivation in primary cHL specimens might be more frequent than previously reported.
FICTION analysis; Hodgkin lymphoma; TNFAIP3 gene; Homozygous deletion
Deregulated c-Myc expression is a hallmark of several human cancers where it promotes proliferation and an aggressive tumour phenotype. Myc overexpression is associated with reduced activity of Rel/NF-κB, transcription factors that control the immune response, cell survival, and transformation, and that are frequently altered in cancer. The Rel/NF-κB family member NFKB2 is altered by chromosomal translocations or deletions in lymphoid malignancies and deletion of the C-terminal ankyrin domain of NF-κB2 augments lymphocyte proliferation.
Precancerous Eμ-Myc-transgenic B cells, Eμ-Myc lymphomas and human Burkitt lymphoma samples were assessed for Nfkb2 expression. The contribution of Nfkb2 to Myc-driven apoptosis, proliferation, and lymphomagenesis was tested genetically in vivo.
Here we report that the Myc oncoprotein suppresses Nfkb2 expression in vitro in primary mouse fibroblasts and B cells, and in vivo in the Eμ-Myc transgenic mouse model of human Burkitt lymphoma (BL). NFKB2 suppression by Myc was also confirmed in primary human BL. Promoter-reporter assays indicate that Myc-mediated suppression of Nfkb2 occurs at the level of transcription. The contribution of Nfkb2 to Myc-driven lymphomagenesis was tested in vivo, where Nfkb2 loss was shown to accelerate lymphoma development in Eμ-Myc transgenic mice, by impairing Myc's apoptotic response.
Nfkb2 is suppressed by c-Myc and harnesses Myc-driven lymphomagenesis. These data thus link Myc-driven lymphomagenesis to the non-canonical NF-κB pathway.
The aim of this study was to evaluate the efficacy of levofloxacin and rifaximin based quadruple regimen as first-line treatment for Helicobacter pylori infection. A prospectively randomized, double-blinded, parallel group, comparative study was performed. Three hundred consecutive H. pylori positive patients were randomized to receive: omeprazole, amoxicillin, clarithromycin (OAC); omeprazole, amoxicillin, levofloxacin (OAL); and omeprazole, amoxicillin, levofloxacin, rifaximin (OAL-R). The eradication rates in the intention to treat (ITT) and per protocol (PP) analyses were: OAC, 77.8% and 85.6%; OAL, 65.3% and 73.6%; and OAL-R, 74.5% and 80.2%. The eradication rate achieved with OAC was higher than with OAL on the ITT (P = 0.05) and PP analysis (P = 0.04). OAL-R regimen was not inferior to OAC. The frequency of moderate to severe adverse effects was significantly higher in OAC treatment group. Especially, diarrhea was most common complaint, and there was a significantly low rate of moderate to severe diarrhea with the rifaximin containing regimen. In conclusion, the levofloxacin and rifaximin based regimen comes up to the standard triple therapy, but has a limited efficacy in a Korean cohort. The rifaximin containing regimen has a very high safety profile for H. pylori eradication therapy.
Helicobacter pylori; Anti-Bacterial Agents; Rifaximin
Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a prototypical cancer that occurs in the setting of chronic inflammation and an important model for understanding how deregulated NF-κB transcriptional activity contributes to malignancy. Most gastric MALT lymphomas require ongoing antigenic stimulation for continued tumor growth, and Stage I disease is usually cured by eradicating the causative microorganism, Helicobacter pylori, with antibiotics. However, in a subset of MALT lymphomas, chromosomal translocations are acquired that render the lymphoma antigen-independent. The recurrent translocation t(11;18)(q21;q21) is associated with failure to respond to antibiotic therapy and increased rate of dissemination. This translocation creates the API2–MALT1 fusion oncoprotein, which comprises the amino terminus of inhibitor of apoptosis 2 (API2 or cIAP2) fused to the carboxy terminus of MALT1. A common characteristic of chromosomal translocations in MALT lymphoma, including t(11;18), is that genes involved in the regulation of the NF-κB transcription factor are targeted by the translocations, and these genetic perturbations thereby result in deregulated, constitutive NF-κB stimulation. In the last decade, great insights into the roles of API2 and MALT1 in NF-κB signaling have been made. For example, recent pivotal studies have uncovered the long sought-after proteolytic activity of MALT1 and have demonstrated its critical involvement in the survival of certain lymphomas. Here, we review the current understanding of the role of MALT1 in normal lymphocyte function and lymphomagenesis. We then highlight our recent work that has revealed an intriguing link between the proteolytic activity of the API2–MALT1 fusion and its ability to influence lymphomagenesis by cleaving a key NF-κB regulatory protein, NF-κB-inducing kinase.
A20; API2–MALT1; Bcl10; chromosomal translocation; lymphoma; MALT1 protease; NIK
Cell-mediated immunity is often suppressed in patients with hematological malignancies. Recently, we found that low T cell receptor (TCR)-CD3 signaling was related to abnormal expression of the negative regulator of nuclear factor kappa B (NF-κB) A20 in acute myeloid leukemia. To investigate the characteristics of T cell immunodeficiency in lymphomas, we analyzed the expression features of A20 and its upstream regulating factor mucosa-associated lymphoid tissue lymphoma translocation gene 1 (MALT1) and genes downstream of NF-κB in patients with different lymphoma subtypes, including T cell non-Hodgkin lymphoma (T-NHL), B cell non-Hodgkin lymphoma (B-NHL) and NK/T cell lymphoma (NK/T-CL).
Real-time PCR was used to determine the expression level of the MALT1, MALT-V1 (variant 1), A20 and NF-κB genes in peripheral blood mononuclear cells (PBMCs) from 24 cases with T-NHL, 19 cases with B-NHL and 16 cases with NK/T-CL, and 31 healthy individuals (HI) served as control.
Significantly lower A20 and NF-κB expression was found in patients with all three lymphoma subtypes compared with the healthy controls. Moreover, the MALT1 expression level was downregulated in all three lymphoma subtypes. A significant positive correlation between the expression level of MALT1 and A20, MALT1-V1 and A20, MALT1-V1 and NF-κB, and A20 and NF-κB was found.
An abnormal MALT1-A20-NF-κB expression pattern was found in patients with lymphoma, which may result a lack of A20 and dysfunctional MALT1 and may be related to lower T cell activation, which is a common feature in Chinese patients with lymphoma. This finding may at least partially explain the molecular mechanism of T cell immunodeficiency in lymphomas.
Lymphoma; Gene expression; MALT1; A20; NF-κB; T cell immunodeficiency
Molecular testing for mutations activating the mitogen-associated protein kinase signaling pathway is being used to help diagnose thyroid carcinomas. However, the prevalence of these mutations in thyroid lymphomas has not been reported. Therefore, we studied the prevalence of BRAF, NRAS, HRAS, and KRAS mutations in 33 thyroid lymphomas and correlated the mutational status with the clinical, pathologic, cytogenetic, and immunophenotypic findings. Eleven cases were also tested for PAX8/PPARγ translocations. The lymphomas included 25 diffuse large B-cell lymphomas, 6 extranodal marginal zone lymphomas of mucosa associated lymphoid tissue type, and 2 follicular lymphomas. Seventeen diffuse large B-cell lymphomas were germinal center type, 6 non-germinal center type and 2 unclassifiable (Hans algorithm). None of the cases had an associated thyroid carcinoma. Mutations of the BRAF gene were identified in 6 (24%) diffuse large B-cell lymphomas (three D594G in germinal center diffuse large B cell lymphomas, two K601N in germinal center diffuse large B cell lymphomas, and one V600E in non-germinal center diffuse large B cell lymphomas) and of the NRAS gene in two (8%) non-germinal center diffuse large B-cell lymphomas (Q61K and Q61H). BRAF and NRAS mutations were not found in any extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue type or follicular lymphoma. HRAS and KRAS mutations were not identified in any of the cases, nor were PAX8/PPARγ translocations found. Thus, interpretation of finding a BRAF or NRAS mutation in the thyroid, particularly in preoperative thyroid aspirates, must take into account the differential diagnosis of a lymphoma. In addition to the diagnostic importance, our data also demonstrate that alteration in the mitogen-associated protein kinase pathway may play a role in the pathogenesis of some large B-cell lymphomas of the thyroid with potential therapeutic implications.
thyroid; lymphoma; BRAF; RAS; mutations
Warthin's tumor is rarely associated with malignant lymphoma. Only 18 cases were reported in the literature so far. In most cases the latter is a low grade process, including Marginal zone/Mucosa associated lymphoid tissue (MALT) type lymphoma, follicular lymphoma, and rarely diffuse large cell lymphoma which may arise de novo or secondary to low grade lymphoma. This study was conducted to determine the prevalence of occult B cell monoclones and genetic alterations in Warthin's tumor. Fourteen cases of Warthin's tumor were stained with antibodies to CD3, CD20, kappa and lambda light chains. On six cases of randomly selected Warthin's tumor, polymerase chain reaction (PCR) of IgH gene rearrangement (IgH-GR) was performed on genomic DNA extracted from formalin-fixed paraffin embedded tissue. One case of primary salivary gland indolent B-cell lymphoma and 3 cases of sialadenitis were analyzed by the same methods for comparison. In all Warthin's tumor and sialadenitis cases most of lymphoid stroma was B cell phenotype and concentrated in germinal centers. T cells were mostly located between germinal centers. No light chain restriction was demonstrable by kappa and lambda immunostains. Molecular genetic studies failed to show IgH-GR by FISH and showed polyclonal by IgH PCR. In contrast, the lymphoma case showed a diffuse proliferation of small B cells with light chain restriction and a minor component of reactive T cells. FISH showed IgH-GR and bcl-2 gene translocation with monoclonality by IgH PCR. Our study concludes that the lymphoid stroma of Warthin's tumor is reactive.
Warthin's tumor; lymphoid stroma; immunohistochemistry; gene rearrangement
The majority of lymphomas of the mucosa-associated lymphoid tissue (MALT)-type arise in the stomach, but extragastric locations are also frequently encountered. Due to previous results indicating that somatostatin receptor (SSTR)-expression distinguishes between gastric and extragastric MALT-type lymphoma, we have initiated a study to evaluate the role of SSTR-scintigraphy for staging and follow-up of patients with extragastric manifestations of MALT-type lymphoma. A total of 30 consecutive patients, including 24 with primary extragastric MALT-type lymphoma, 5 patients with dissemination to extragastric sites (including colon, lung, parotid, ocular adnexa and breast) following an initial gastric MALT-lymphoma and one patient with spread to stomach, lung and lymph nodes following parotid lymphoma were prospectively studied. All patients had histologically verified MALT-type lymphoma: 2 patients had lymphoma presenting in the lung, 9 in the ocular adnexa, 7 had lymphomas in the parotid, 2 patients had disease located in the breast, 3 patients had lymph-node relapse following MALT-type lymphoma of the parotid, the lacrimal gland and the thyroid, and 1 had primary MALT-lymphoma of the liver. All patients underwent SSTR-scintigraphy using 111In-DTPA-D-Phe1-Octreotide (111In-OCT) before initiation of therapy, while 13 also had a second scan after treatment. The results of gamma camera imaging were compared to conventional staging. No positive scans could be obtained in patients with dissemination following gastric lymphoma, while all patients with primary extragastric lymphoma had positive scans at the site of histologically documented involvement before initiation of therapy. In addition, also the patient with secondary spread to stomach, lung and lymph nodes was positive in all documented lymphoma sites. In one patient, focal tracer uptake in projection to the maxillary sinus was documented, which was bioptically verified as inflammation. In the scans performed after therapy, focal tracer accumulation in the left orbit indicated persistance of disease following irradiation in one patient with otherwise negative work-up, which was verified by MRI and biopsy 6 months later. In another patient, a positive scan indicated disease relapse in the lacrimal gland 9 months before clinical verification by means of ultrasound. In one patient, a focus not present in the pretherapeutic scan was found in the ethmoidal sinus, corresponding to a hyperplastic polyp. Both SST-scan as well as CT indicated disease persistance in one case, while negative scans corresponding to complete remission as judged by conventional staging were obtained following therapy in the remaining patients, and absence of relapse has been confirmed for a median follow-up of 2 years. These results indicate that 111In-OCT is an excellent tool for staging and non-invasive therapy-monitoring in extragastric MALT-type lymphomas. These data further confirm our initial finding that gastric MALT-type lymphomas do not express relevant amounts of respective SSTR, and that SSTR-scanning is able to distinguish between gastric vs extragastric origin of MALT-type lymphoma irrespective of the site of presentation.© 2001 Cancer Research Campaign http://www.bjcancer.com
somatostatin; extraintestinal MALT-lymphoma; scintigraphy