Gene Summary

Gene:MALT1; MALT1 paracaspase
Aliases: MLT, MLT1, IMD12
Summary:This gene has been found to be recurrently rearranged in chromosomal translocation with two other genes - baculoviral IAP repeat-containing protein 3 (also known as apoptosis inhibitor 2) and immunoglobulin heavy chain locus - in mucosa-associated lymphoid tissue lymphomas. The protein encoded by this gene may play a role in NF-kappaB activation. Two alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, Jul 2008]
Databases:OMIM, HGNC, GeneCard, Gene
Protein:mucosa-associated lymphoid tissue lymphoma translocation protein 1
Source:NCBIAccessed: 18 August, 2015


What does this gene/protein do?
Show (37)
Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 18 August 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Skin Cancer
  • Polymerase Chain Reaction
  • Transcription
  • Lung Cancer
  • Cancer Gene Expression Regulation
  • Staging
  • Chromosome 18
  • Sputum
  • Chromosome 14
  • NF-kappa B
  • Helicobacter pylori and cancer
  • Adolescents
  • BIRC3
  • Chromosome Aberrations
  • Virulence
  • Stomach Cancer
  • MALT Lymphoma
  • Diffuse Large B-Cell Lymphoma
  • Proteins
  • Zinc Fingers
  • Thyroiditis, Autoimmune
  • DNA Sequence Analysis
  • Salivary Glands, Minor
  • Immunoglobulin Heavy Chains
  • Helicobacter Infections
  • Molecular Sequence Data
  • Caspases
  • Neoplasm Proteins
  • B-Cell Lymphoma
  • Inhibitor of Apoptosis Proteins
  • FISH
  • B-Lymphocytes
  • Chromosome 11
  • Oncogene Fusion Proteins
  • Immunohistochemistry
  • Gene Rearrangement
  • Base Sequence
  • Signal Transducing Adaptor Proteins
  • Receptors, Antigen
  • MALT1
  • Apoptosis
Tag cloud generated 18 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: MALT1 (cancer-related)

Ishikawa H, Iwamuro M, Okada H, et al.
Recurrence after radiotherapy for gastric mucosa-associated lymphoid tissue (MALT) lymphoma with trisomy 18.
Intern Med. 2015; 54(8):911-6 [PubMed] Related Publications
A 36-year-old Japanese woman presented with extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) in the stomach. The gastric lesions only partially improved after eradication therapy for Helicobacter pylori. A fluorescence in situ hybridization analysis revealed no fusion genes of API2-MALT1, although trisomy of chromosome 18 was identified. Radiation therapy was initiated to treat the gastric lymphoma lesions, resulting in complete remission. However, MALT lymphoma recurred in the stomach 16 months later. This case indicates that intensive follow-up is required for MALT lymphoma associated with chromosomal aberrations in order to detect early relapse.

Ma Y, Liao Z, Xu Y, et al.
Characteristics of CARMA1-BCL10-MALT1-A20-NF-κB expression in T cell-acute lymphocytic leukemia.
Eur J Med Res. 2014; 19:62 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Knowledge of the oncogenic signaling pathways of T-cell acute lymphoblastic leukemia (T-ALL) remains limited. Constitutive aberrant activation of the nuclear factor kappa B (NF-κB) signaling pathway has been detected in various lymphoid malignancies and plays a key role in the development of these carcinomas. The zinc finger-containing protein, A20, is a central regulator of multiple NF-κB-activating signaling cascades. A20 is frequently inactivated by deletions and/or mutations in several B-and T-cell lymphoma subtypes. However, few A20 mutations and polymorphisms have been reported in T-ALL. Thus, it is of interest to analyze the expression characteristics of A20 and its regulating factors, including upstream regulators and the CBM complex, which includes CARMA1, BCL10, and MALT1.
METHODS: The expression levels of CARMA1, BCL10, MALT1, A20, and NF-κB were detected in peripheral blood mononuclear cells (PBMCs) from 21 patients with newly diagnosed T-ALL using real-time PCR, and correlations between the aberrant expression of these genes in T-ALL was analyzed. Sixteen healthy individuals, including 10 males and 6 females, served as controls.
RESULTS: Significantly lower A20 expression was found in T-ALL patients (median: 4.853) compared with healthy individuals (median: 8.748; P = 0.017), and significantly increased expression levels of CARMA1 (median: 2.916; P = 0.034), BCL10 (median: 0.285; P = 0.033), and MALT1 (median: 1.201; P = 0.010) were found in T-ALL compared with the healthy individuals (median: 1.379, 0.169, and 0.677, respectively). In contrast, overexpression of NF-κB (median: 0.714) was found in T-ALL compared with healthy individuals (median: 0.335; P = 0.001). A negative correlation between the MALT1 and A20 expression levels and a positive correlation between CARMA1 and BCL10 were found in T-ALL and healthy individuals. However, no negative correlation was found between A20 and NF-κB and the MALT1 and NF-κB expression level in the T-ALL group.
CONCLUSIONS: We characterized the expression of the CARMA-BCL10-MALT1-A20-NF-κB pathway genes in T-ALL. Overexpression of CARMA-BCL10-MALT in T-ALL may contribute to the constitutive cleavage and inactivation of A20, which enhances NF-κB signaling and may be related to T-ALL pathogenesis.

Steinhardt JJ, Peroutka RJ, Mazan-Mamczarz K, et al.
Inhibiting CARD11 translation during BCR activation by targeting the eIF4A RNA helicase.
Blood. 2014; 124(25):3758-67 [PubMed] Free Access to Full Article Related Publications
Human diffuse large B-cell lymphomas (DLBCLs) often aberrantly express oncogenes that generally contain complex secondary structures in their 5' untranslated region (UTR). Oncogenes with complex 5'UTRs require enhanced eIF4A RNA helicase activity for translation. PDCD4 inhibits eIF4A, and PDCD4 knockout mice have a high penetrance for B-cell lymphomas. Here, we show that on B-cell receptor (BCR)-mediated p70s6K activation, PDCD4 is degraded, and eIF4A activity is greatly enhanced. We identified a subset of genes involved in BCR signaling, including CARD11, BCL10, and MALT1, that have complex 5'UTRs and encode proteins with short half-lives. Expression of these known oncogenic proteins is enhanced on BCR activation and is attenuated by the eIF4A inhibitor Silvestrol. Antigen-experienced immunoglobulin (Ig)G(+) splenic B cells, from which most DLBCLs are derived, have higher levels of eIF4A cap-binding activity and protein translation than IgM(+) B cells. Our results suggest that eIF4A-mediated enhancement of oncogene translation may be a critical component for lymphoma progression, and specific targeting of eIF4A may be an attractive therapeutic approach in the management of human B-cell lymphomas.

Agarwal NK, Zhu X, Gagea M, et al.
PHLPP2 suppresses the NF-κB pathway by inactivating IKKβ kinase.
Oncotarget. 2014; 5(3):815-23 [PubMed] Free Access to Full Article Related Publications
The NF-κB growth pathway is constitutively activated in many cancers but its activation mechanism is unclear in most cases. We show that PHLPP2 interacts with IKKβ kinase, decreases its phosphorylation and the subsequent NF-κB activation in cancer cells. PHLPP2 is progressively lost in glioma and colorectal cancer and acts as a bona fide tumor suppressor, depending on IKKβ expression in cells. Physiologically, IKKβ activation by growth factors requires the formation of the Bcl10-MALT1 ubiquitin-ligase complex leading to NEMO/IKKγ non-degradative ubiquitination and IKKβ phosphorylation. PHLPP2 opposes the formation of this complex through interaction with Bcl10 and competitive displacement of MALT1 from Bcl10. Conversely, PHLPP2 loss enhances Bcl10-MALT1 complex formation, NEMO ubiquitination and subsequent IKKβ phosphorylation, resulting in increased NF-κB-dependent transcription of multiple target genes. Our results reveal PHLPP2 as a new biomarker of cancer progression, and implicate it as major negative regulator of NF-κB signaling.

Sugimoto KJ, Imai H, Shimada A, et al.
Diffuse large B-cell lymphoma of the uterus suspected of having transformed from a marginal zone B-cell lymphoma harboring trisomy 18: a case report and review of the literature.
Int J Clin Exp Pathol. 2013; 6(12):2979-88 [PubMed] Free Access to Full Article Related Publications
The patient was a 72-year-old female with the chief complaint of abdominal fullness. A giant primary myoma of the uterine cervix was suspected, and total hysterectomy was performed. Based on a postoperative histopathological examination of the tumor a diagnosis of diffuse large B-cell lymphoma (DLBCL) was made in the uterus and a mass in the greater omentum was diagnosed as a marginal zone B-cell lymphoma (MZBCL). No flow-cytometry studies or chromosome or gene examinations were performed on a fresh specimen. The results of an examination of a paraffin block histopathology specimen by fluorescence in-situ hybridization (FISH) showed no mucosa associated lymphoid tissue lymphoma translocation gene 1 (MALT1) (18q21.1), B-cell lymphoma 2 (BCL2) (18q21.3), or BCL6 (3q27) split signals in either the uterus or the greater omentum, however, trisomy 18 was detected in approximately 50%-70% of the tumor cells in both the uterus and the greater omentum. Trisomy 18 was present in around 15-33% of the DLBCL cells and MZBCL cells. These findings suggested a strong possibility that the tumor cells in the uterus and greater omentum were the same clone and that transformation from MZBCL to DLBCL had occurred. Since DLBCLs that result from a transformation usually have a worse outcome than de novo DLBCLs, even when a DLBCL seems to have originated in the uterus the surrounding tissue should always be examined, and caution should be exercised in regard to transformation from a low-grade B-cell lymphoma to a DLBCL.

Ko HM, Geddie WR, Boerner SL, et al.
Cytomorphological and clinicopathological spectrum of pulmonary marginal zone lymphoma: the utility of immunophenotyping, PCR and FISH studies.
Cytopathology. 2014; 25(4):250-8 [PubMed] Related Publications
OBJECTIVE: To review cytomorphological criteria and clinicopathological findings in combination with ancillary tests for the specific diagnosis of pulmonary marginal zone lymphoma (MZL) in fine needle aspiration (FNA) specimens.
METHODS: Cases of pulmonary MZL diagnosed using cytological specimens from 2005 to 2012 were retrieved and reviewed by three cytopathologists. Results of immunophenotypic analysis, interphase fluorescence in situ hybridization (FISH) and molecular assays were collated, together with clinical information and imaging data. Concurrent surgical biopsies were also retrieved.
RESULTS: Fifteen lung FNA specimens were identified. The smears consisted predominantly of small centrocyte-like cells. Marked plasma cell differentiation was evident in 11 cases. All cases with slides available showed tissue fragments with lymphoid tangles (TFLTs). Multinucleated giant cells were present in nine cases, two of which showed granulomas. Immunophenotyping confirmed B-cell clonality in all cases. B-cell clonality was detected by polymerase chain reaction (PCR) in two samples. FISH identified MALT1 translocation in four of 10 cases tested and trisomy 3 in three of four cases. Concurrent surgical biopsies were diagnosed independently as MZL in seven cases.
CONCLUSIONS: Cytology smears from lung FNA samples consisting of small lymphoid cells with a relative abundance of plasma cells or plasmacytoid cells and large TFLTs should prompt immunophenotyping and other ancillary studies, even if multinucleated giant cells and poorly formed granulomas are also identified. Specific diagnosis of pulmonary MZL in FNA samples can be rendered on the basis of morphological features coupled with the demonstration of B-cell clonality by immunophenotyping or PCR and cytogenetic abnormalities by FISH.

Kawamoto Y, Ohyama Y, Chiba T, et al.
Proteomic identification of keratin alterations with enhanced proliferation of oral carcinoma cells by loss of mucosa-associated lymphoid tissue 1 expression.
Int J Oncol. 2013; 43(3):729-36 [PubMed] Related Publications
Progression of oral carcinomas associates with aberrant activation and inactivation of molecules that work in established or unknown pathways. Although mucosa‑associated lymphoid tissue 1 (MALT1) expressed in normal oral epithelium is inactivated in the aggressive subset of carcinomas with worse prognosis, phenotypic changes of carcinoma cells upon the loss of expression is unknown. We performed a proteomic analysis to identify MALT1‑regulated proteins in oral carcinoma cells. Four different keratins were included in the ten most abundantly changed proteins. K8/18 were upregulated in MALT1 stably‑expressing carcinoma cells and K5/14 in MALT1‑marginal control cells. K8/18 upregulation and K5/14 downregulation were MALT1 dose‑dependent and observed in a series of oral carcinoma cells. MALT1 suppressed cell proliferation (0.52-fold, P<0.01) and its dominant-negative form stimulated it (1.33-fold, P<0.01). The decreased proliferation associated with reduction of cyclin D1, which was recovered by the short interfering RNA against MALT1. Taken together, loss of MALT1 expression alters keratin expression and enhances proliferation of carcinoma cells, and may progress oral carcinomas into the advanced state.

Ohyama Y, Kawamoto Y, Chiba T, et al.
Inhibition of TGF-β and EGF pathway gene expression and migration of oral carcinoma cells by mucosa-associated lymphoid tissue 1.
Br J Cancer. 2013; 109(1):207-14 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Expression of mucosa-associated lymphoid tissue 1 (MALT1) is inactivated in oral carcinoma patients with worse prognosis. However, the role in carcinoma progression is unknown. Unveiling genes under the control of MALT1 is necessary to understand the pathology of carcinomas.
METHODS: Gene data set differentially transcribed in MALT1-stably expressing and -marginally expressing oral carcinoma cells was profiled by the microarray analysis and subjected to the pathway analysis. Migratory abilities of cells in response to MALT1 were determined by wound-healing assay and time-lapse analysis.
RESULTS: Totally, 2933 genes upregulated or downregulated in MALT1-expressing cells were identified. The subsequent pathway analysis implicated the inhibition of epidermal growth factor and transforming growth factor-β signalling gene expression, and highlighted the involvement in the cellular movement. Wound closure was suppressed by wild-type MALT1 (66.4%) and accelerated by dominant-negative MALT1 (218.6%), and the velocities of cell migration were increased 0.2-fold and 3.0-fold by wild-type and dominant-negative MALT1, respectively.
CONCLUSION: These observations demonstrate that MALT1 represses genes activating the aggressive phenotype of carcinoma cells, and suggest that MALT1 acts as a tumour suppressor and that the loss of expression stimulates oral carcinoma progression.

Rosebeck S, Rehman AO, Apel IJ, et al.
The API2-MALT1 fusion exploits TNFR pathway-associated RIP1 ubiquitination to promote oncogenic NF-κB signaling.
Oncogene. 2014; 33(19):2520-30 [PubMed] Free Access to Full Article Related Publications
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.

Valera A, López-Guillermo A, Cardesa-Salzmann T, et al.
MYC protein expression and genetic alterations have prognostic impact in patients with diffuse large B-cell lymphoma treated with immunochemotherapy.
Haematologica. 2013; 98(10):1554-62 [PubMed] Free Access to Full Article Related Publications
MYC alterations influence the survival of patients with diffuse large B-cell lymphoma. Most studies have focused on MYC translocations but there is little information regarding the impact of numerical alterations and protein expression. We analyzed the genetic alterations and protein expression of MYC, BCL2, BCL6, and MALT1 in 219 cases of diffuse large B-cell lymphoma. MYC rearrangement occurred as the sole abnormality (MYC single-hit) in 3% of cases, MYC and concurrent BCL2 and/or BCL6 rearrangements (MYC double/triple-hit) in 4%, MYC amplifications in 2% and MYC gains in 19%. MYC single-hit, MYC double/triple-hit and MYC amplifications, but not MYC gains or other gene rearrangements, were associated with unfavorable progression-free survival and overall survival. MYC protein expression, evaluated using computerized image analysis, captured the unfavorable prognosis of MYC translocations/amplifications and identified an additional subset of patients without gene alterations but with similar poor prognosis. Patients with tumors expressing both MYC/BCL2 had the worst prognosis, whereas those with double-negative tumors had the best outcome. High MYC expression was associated with shorter overall survival irrespectively of the International Prognostic Index and BCL2 expression. In conclusion, MYC protein expression identifies a subset of diffuse large B-cell lymphoma with very poor prognosis independently of gene alterations and other prognostic parameters.

Pelzer C, Cabalzar K, Wolf A, et al.
The protease activity of the paracaspase MALT1 is controlled by monoubiquitination.
Nat Immunol. 2013; 14(4):337-45 [PubMed] Related Publications
The protease activity of the paracaspase MALT1 is central to lymphocyte activation and lymphomagenesis, but how this activity is controlled remains unknown. Here we identify a monoubiquitination of MALT1 on Lys644 that activated the protease function of MALT1. Monoubiquitinated MALT1 had enhanced protease activity, whereas a ubiquitination-deficient MALT1 mutant with replacement of that lysine with arginine (MALT1(K644R)) had less protease activity, which correlated with impaired induction of interleukin 2 (IL-2) via the T cell antigen receptor in activated T cells. Expression of MALT1(K644R) diminished the survival of cells derived from diffuse large B cell lymphoma of the activated B cell-like subtype (ABC DLBCL), which require constitutive protease activity of MALT1 for survival. Thus, monoubiquitination of MALT1 is essential for its catalytic activation and is therefore a potential target for the treatment of ABC-DLBCL and for immunomodulation.

Choi YJ, Kim N, Paik JH, et al.
Characteristics of Helicobacter pylori-positive and Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue lymphoma and their influence on clinical outcome.
Helicobacter. 2013; 18(3):197-205 [PubMed] Related Publications
BACKGROUND: To compare clinicopathologic and molecular characteristics of low-grade gastric mucosa-associated lymphoid tissue lymphoma depending on Helicobacter pylori positivity and to find out a predictive factor for unresponsiveness to Helicobacter pylori eradication therapy in Korea.
METHODS: A total of 53 Helicobacter pylori-positive and 13 negative mucosa-associated lymphoid tissue lymphoma patients were enrolled, and tissues from 21 patients were investigated to examine the presence of t(11;18)(q21;q21) with fluorescence in situ hybridization. Clinicopathologic features such as the endoscopic appearance, dominant site of lesion, depth of invasion, clinical stage, and the existence of MALT1 gene rearrangement were compared between these two groups. Fifty-six patients who underwent H. pylori eradication therapy were divided into responder and nonresponder groups. The two groups were analyzed to calculate odds ratios for resistance to the eradication.
RESULTS: Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue lymphoma patients averaged a more advanced clinical stage than H. pylori-positive (p = .023) patients. The frequency of t(11;18)/API2-MALT1 did not differ between H. pylori-positive (45.5%) and H. pylori-negative cases (55.6%). Thirty-eight of 51 (74.5%) H. pylori-positive patients achieved complete regression after the eradication, while 2 of 5 (40%) H. pylori-negative patients obtained regression. Presence of lesions in both distal and proximal parts of stomach (p = .041) and bearing of t(11;18)(q21;q21) (p = .007) were predictors for nonresponsiveness for H. pylori eradication.
CONCLUSIONS: Helicobacter pylori eradication could be performed as a primary therapy regardless of H. pylori status, and assessing t(11;18)/API2-MALT1 would be considered after failure to remission by H. pylori eradication.

Fontan L, Yang C, Kabaleeswaran V, et al.
MALT1 small molecule inhibitors specifically suppress ABC-DLBCL in vitro and in vivo.
Cancer Cell. 2012; 22(6):812-24 [PubMed] Free Access to Full Article Related Publications
MALT1 cleavage activity is linked to the pathogenesis of activated B cell-like diffuse large B cell lymphoma (ABC-DLBCL), a chemoresistant form of DLBCL. We developed a MALT1 activity assay and identified chemically diverse MALT1 inhibitors. A selected lead compound, MI-2, featured direct binding to MALT1 and suppression of its protease function. MI-2 concentrated within human ABC-DLBCL cells and irreversibly inhibited cleavage of MALT1 substrates. This was accompanied by NF-κB reporter activity suppression, c-REL nuclear localization inhibition, and NF-κB target gene downregulation. Most notably, MI-2 was nontoxic to mice, and displayed selective activity against ABC-DLBCL cell lines in vitro and xenotransplanted ABC-DLBCL tumors in vivo. The compound was also effective against primary human non-germinal center B cell-like DLBCLs ex vivo.

Saito Y, Suzuki H, Tsugawa H, et al.
Overexpression of miR-142-5p and miR-155 in gastric mucosa-associated lymphoid tissue (MALT) lymphoma resistant to Helicobacter pylori eradication.
PLoS One. 2012; 7(11):e47396 [PubMed] Free Access to Full Article Related Publications
microRNAs (miRNAs) are small non-coding RNAs that can function as endogenous silencers of target genes and play critical roles in human malignancies. To investigate the molecular pathogenesis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma, the miRNA expression profile was analyzed. miRNA microarray analysis with tissue specimens from gastric MALT lymphomas and surrounding non-tumor mucosae revealed that a hematopoietic-specific miRNA miR-142 and an oncogenic miRNA miR-155 were overexpressed in MALT lymphoma lesions. The expression levels of miR-142-5p and miR-155 were significantly increased in MALT lymphomas which do not respond to Helicobacter pylori (H. pylori) eradication. The expression levels of miR-142-5p and miR-155 were associated with the clinical courses of gastric MALT lymphoma cases. Overexpression of miR-142-5p and miR-155 was also observed in Helicobacter heilmannii-infected C57BL/6 mice, an animal model of gastric MALT lymphoma. In addition, miR-142-5p and miR-155 suppress the proapoptotic gene TP53INP1 as their target. The results of this study indicate that overexpression of miR-142-5p and miR-155 plays a critical role in the pathogenesis of gastric MALT lymphoma. These miRNAs might have potential application as therapeutic targets and novel biomarkers for gastric MALT lymphoma.

Mationg-Kalaw E, Tan LH, Tay K, et al.
Does the proliferation fraction help identify mature B cell lymphomas with double- and triple-hit translocations?
Histopathology. 2012; 61(6):1214-8 [PubMed] Related Publications
AIMS: The entity 'B cell lymphoma, unclassifiable, with features intermediate between diffuse large B cell lymphoma (DLBCL) and Burkitt lymphoma (BL)' refers to B cell neoplasms that share overlapping characteristics of BL and DLBCL. A subset of these 'grey-zone lymphomas' possesses C-MYC and IGH translocations but, in addition, contains additional rearrangements of BCL2 and/or BCL6 genes. The aim of this study was to investigate if the proliferation fraction by Ki67 immunostaining can be used to identify such double-/triple-hit lymphomas.
METHODS AND RESULTS: We studied 492 cases of mature aggressive B cell neoplasms by histology, immunohistochemistry and interphase fluorescence in-situ hybridization (FISH) using break-apart probes against C-MYC, BCL2, BCL6, IGH, MALT1, PAX5 and CCND1. Forty Burkitt lymphomas and 28 cases of MYC(+) double-/triple-hit lymphomas were identified. Of the latter, 77% and 54% displayed proliferation fractions exceeding 75% and 90%, respectively. With a cut-off of >75% by Ki67 immunostaining, the sensitivity and specificity for detection of MYC(+) double/triple translocations was 0.77 and 0.36. Raising the proliferation fraction criterion to >90% improved the specificity to 0.62 at the expense of a low sensitivity of 0.54.
CONCLUSIONS: Immunostaining for Ki67 is not a useful approach to prescreen B cell lymphomas for MYC(+) double/triple translocations.

Chan W, Schaffer TB, Pomerantz JL
A quantitative signaling screen identifies CARD11 mutations in the CARD and LATCH domains that induce Bcl10 ubiquitination and human lymphoma cell survival.
Mol Cell Biol. 2013; 33(2):429-43 [PubMed] Free Access to Full Article Related Publications
Antigen receptor signaling to NF-κB, essential for normal lymphocyte activation, is dysregulated in several types of lymphoma. During normal signaling, the multidomain adapter CARD11 transitions from a closed, inactive state to an open, active scaffold that assembles a multiprotein complex, leading to NF-κB activation. The regulation of CARD11 scaffold function is bypassed by lymphoma-associated oncogenic CARD11 mutations that induce spontaneous signaling. We report an unbiased high-throughput quantitative signaling screen that identifies new CARD11 hyperactive variants and defines a LATCH domain that functions with the CARD to promote CARD11 autoinhibition. Gain-of-function mutations in the LATCH or CARD disrupt inhibitory domain binding, promote Bcl10 association, and induce Bcl10 ubiquitination, NF-κB activation, and human lymphoma cell survival. Our results identify CARD11 mutations with oncogenic potential, provide a mechanistic explanation for their signaling potency, and offer a straightforward method for the discovery of variants that promote the tumorigenesis of NF-κB-dependent lymphomas.

Kuper-Hommel MJ, Schreuder MI, Gemmink AH, van Krieken JH
T(14;18)(q32;q21) involving MALT1 and IGH genes occurs in extranodal diffuse large B-cell lymphomas of the breast and testis.
Mod Pathol. 2013; 26(3):421-7 [PubMed] Related Publications
Primary B-cell lymphoma of the testis, breast and thyroid are rare and data concerning cytogenetic aberrations at these extranodal sites are scarce. We examined the presence of extranodal marginal zone lymphoma-associated translocations, t(11;18)(q21;q21), t(1;14)(p22;q32), t(14;18)(q32;q21), t(3;14)(p14.1;q32) and numerical aberrations of chromosomes 1, 3, 12 and 18 by fluorescence in situ hybridization in 6 extranodal marginal zone lymphomas and 24 diffuse large B-cell lymphomas with (n=9) or without (n=15) marginal zone lymphoma components, with primary localizations in the breast (n=15), testis (n=9) and thyroid (n=6). We found t(14;18)(q32;q21), with breakpoints in IGH and MALT1, in one testicular diffuse large B-cell lymphoma and in two diffuse large B-cell lymphomas of the breast. No other translocations, amplifications or deletions involving IGH, BCL-10, BCL-2, MALT1 and IAP2 were detected. Numerical aberrations occurred in 67% of the lymphomas, 67% of extranodal marginal zone lymphomas, 56% of diffuse large B-cell lymphomas with marginal zone lymphoma components and in 73% of 'de novo' diffuse large B-cell lymphomas. These included 78% of testis, 67% of thyroid and 60% of breast lymphomas, and included mainly trisomy 18 (n=16), trisomy 3 (n=8) and trisomy 1 (n=3). One testicular diffuse large B-cell lymphoma harbored both t(14;18)(q32;q21) and trisomy 3. Our results indicate that at least a few cases of diffuse large B-cell lymphoma of the testis and the breast belong to the spectrum of extranodal marginal zone lymphoma.

Stary S, Vinatzer U, Müllauer L, et al.
t(11;14)(q23;q32) involving IGH and DDX6 in nodal marginal zone lymphoma.
Genes Chromosomes Cancer. 2013; 52(1):33-43 [PubMed] Related Publications
Nodal marginal zone lymphoma (NMZL) is a primary nodal B-cell lymphoma that shares morphological and immunophenotypic characteristics with extranodal and splenic marginal zone lymphoma. Data on altered genes and signaling pathways are scarce in this rare tumor entity. To gain further insights into the genetic background of NMZL, seven cases were investigated by microarray analysis, G-banding, and FISH. Chromosomal imbalances were observed in 3/7 cases (43%) with gains of chromosome arms 1q, 8q, and 12q being the most frequent findings. Furthermore, we identified a translocation t(11;14)(q23;q32) involving IGH and DDX6. Chromosomal walking, expression analysis, siRNA-mediated gene knockdown and a yeast two hybrid screen were performed for further characterization of the translocation in vitro. In siRNA experiments, DDX6 appeared not to be involved in NF-κB activation as frequently observed for genes promoting lymphomagenesis but was found to interfere with the expression of BCL6 and BCL2 in an NF-κB independent manner. In conclusion, we identified several unbalanced aberrations and a t(11;14) involving IGH and DDX6 providing evidence for a contribution of DDX6 to lymphomagenesis by deregulation of BCL6 in NMZL.

Flossbach L, Holzmann K, Mattfeldt T, et al.
High-resolution genomic profiling reveals clonal evolution and competition in gastrointestinal marginal zone B-cell lymphoma and its large cell variant.
Int J Cancer. 2013; 132(3):E116-27 [PubMed] Related Publications
We studied marginal zone B-cell lymphomas of the gastrointestinal tract including seven small cell lymphomas, eight large cell areas of composite lymphomas and 13 large cell variants using SNP array profiling. We found an increase of genomic complexity with lymphoma progression from small to large cytology, and identified gains of prominent (proto) oncogenes such as REL, BCL11A, ETS1, PTPN1, PTEN and KRAS which were found exclusively in the large cell variants. Copy numbers of ADAM3A, SCAPER and SIRPB1 were varying between the three different modes of presentation, hence suggestive for aberrations associated with progression from small to large cell lymphoma. The number of aberrations was slightly higher in the large cell part of composite lymphomas than in large cell lymphomas, suggesting that clonal selection takes place and that composite lymphomas are in a transition state. To further investigate this, we comparatively analyzed samples of two morphologically different regions of the same small cell tumor with a BIRC3-MALT1 translocation, as well as material acquired at two different time points from one composite lymphoma. We found genomic heterogeneity in both cases, supporting the theory of competing subclones in the evolution and progression of extranodal marginal zone B-cell lymphoma.

Hirota-Kawadobora M, Matsuda K, Yamauchi K, et al.
Waldenström macroglobulinemia transforming from t (11;18) (q21;q21) -negative gastric MALT lymphoma after systemic dissemination.
Rinsho Byori. 2012; 60(6):528-35 [PubMed] Related Publications
AIM: We here describe the clinical course of a 70-year-old male patient with Waldenström macroglobulinemia (WM) putatively transformed from refractory mucosa-associated lymphoid tissue lymphoma (MALTL).
METHODS: Immunological staining was performed on formalin-fixed, paraffin-embedded tissue sections, and M-protein and cryoglobulin were identified by immunofixation electrophoresis and the cold precipitation method. Chromosome translocation was analyzed by the G-banded karyotype, and API2/MALT1 fusion gene underwent fluorescent in situ hybridization. Multiplex polymerase chain reaction was performed to analyze the VH-JH or DH-JH rearrangements of the IGH gene.
RESULTS: At diagnosis, the WM patient had monoclonal IgM with cryoglobulinemia and hyperviscosity syndrome. Eight years before developing WM, the patient experienced the onset of typical gastric MALT-L with H. pylori infection, but in spite of negative for chromosome translocation, t (11;18) and the successful eradication of H. pylori, the MALT-L relapsed repeatedly, and finally led to systemic metastasis. The lymphoma cells also infiltrated the large intestine and spleen. Immunoglobulin gene analyses of cellular clonality revealed that the same clone had been present in the stomach, bone marrow (BM) at the onset of MALT L, and in the BM at the diagnosis of WM.
CONCLUSIONS: In this case, lymphoma developed as H. pylori-associated gastric MALT-L with negative for t (11;18), and might be transformed into MW during the systemic metastasis.

Liguori G, Cantile M, Cerrone M, et al.
Breast MALT lymphomas: a clinicopathological and cytogenetic study of 9 cases.
Oncol Rep. 2012; 28(4):1211-6 [PubMed] Related Publications
Primary breast mucosa-associated lymphoid tissue (MALT) lymphomas are uncommon and restricted diagnostic criteria should be used to exclude breast involvement by systemic lymphomas. The molecular pathogenesis of primary breast MALT lymphomas is not clear because of the rarity of the disease. Generally the molecular studies of MALT lymphoma in extranodal sites have shown the presence of different chromosomal aberrations, mutually exclusive with substantial differences in their frequency relatively to topographic localization. Few cases of breast MALT lymphomas in the literature have been assessed for MALT lymphoma-associated translocations and BCL10 expression, underlying their rarity in primary breast MALT lymphomas. In our study, we analyzed a series of nine cases of primary breast MALT lymphomas. FISH results showed evidence of MALT1 gene rearrangements in four primary breast lymphomas, in particular three cases with t(11;18)(q21;q21) and one case with t(14;18)(q32;q21). In addition, BCL10 gene rearrangement was not observed. There was no evidence of BCL10 gene translocation in any of the neoplasms assessed. Our data indicate that MALT1 gene rearrangements are not rare in primary breast MALT lymphoma in contrast with results of previous series. Finally, t(11;18) has been observed to be significantly associated with high intensity cytoplasmic BCL10 expression underlying cross-talk between MALT1 and BCL10 pathways in the pathogenesis of MALT lymphomas.

Chiarini A, Marconi M, Pacchiana R, et al.
Role-shifting PKCζ fosters its own proapoptotic destruction by complexing with Bcl10 at the nuclear envelope of human cervical carcinoma cells: a proteomic and biochemical study.
J Proteome Res. 2012; 11(8):3996-4012 [PubMed] Related Publications
Many features of deadly human cervical cancers (HCCs) still require elucidation. Among HCC-derived cell lines, here we used the C4-I one since its quantitative gene expression pattern most closely mimics invasive HCCs, including protein kinase-Cζ (PKCζ) overexpression. Via proteomic, bioinformatic, and biochemical approaches we identified 31 and 33 proteins co-immunoprecipitating with PKCζ from nuclear membranes (NMs) of, respectively, untreated or VP-16-exposed C4-I cells. Such proteins belonged to eight functional groups, whose compositions and relative sizes changed with either context. Of the 56 proteins identified, only eight were shared between the two subproteomes, including Bcl10. Surprisingly, proteins known to associate with Bcl10, like Carma1/3 and Malt1, in so-called CBM signalosomes were absent. Notably, in VP-16-treated C4-I cells, PKCζ•Bcl10 complexes increasingly accrued at NMs, where PKCζ phosphorylated Bcl10, as PKCζ also did in vitro and in cell-free systems, both processes being thwarted by interfering RNA (iRNA) PKCζ depletion. Caspase-3 was associated with PKCζ•Bcl10 complexes and proteolyzed PKCζ leading to its inactivation/destruction; both events were prevented by Bcl10 iRNA suppression. Thus, PKCζ's molecular interactions and functional roles changed strikingly according to the untreated or apoptogen-treated cells context, and by complexing with Bcl10, PKCζ surprisingly favored its own demise, which suggests both proteins as HCCs therapeutic targets.

Vicente-Dueñas C, Fontán L, Gonzalez-Herrero I, et al.
Expression of MALT1 oncogene in hematopoietic stem/progenitor cells recapitulates the pathogenesis of human lymphoma in mice.
Proc Natl Acad Sci U S A. 2012; 109(26):10534-9 [PubMed] Free Access to Full Article Related Publications
Chromosomal translocations involving the MALT1 gene are hallmarks of mucosa-associated lymphoid tissue (MALT) lymphoma. To date, targeting these translocations to mouse B cells has failed to reproduce human disease. Here, we induced MALT1 expression in mouse Sca1(+)Lin(-) hematopoietic stem/progenitor cells, which showed NF-κB activation and early lymphoid priming, being selectively skewed toward B-cell differentiation. These cells accumulated in extranodal tissues and gave rise to clonal tumors recapitulating the principal clinical, biological, and molecular genetic features of MALT lymphoma. Deletion of p53 gene accelerated tumor onset and induced transformation of MALT lymphoma to activated B-cell diffuse large-cell lymphoma (ABC-DLBCL). Treatment of MALT1-induced lymphomas with a specific inhibitor of MALT1 proteolytic activity decreased cell viability, indicating that endogenous Malt1 signaling was required for tumor cell survival. Our study shows that human-like lymphomas can be modeled in mice by targeting MALT1 expression to hematopoietic stem/progenitor cells, demonstrating the oncogenic role of MALT1 in lymphomagenesis. Furthermore, this work establishes a molecular link between MALT lymphoma and ABC-DLBCL, and provides mouse models to test MALT1 inhibitors. Finally, our results suggest that hematopoietic stem/progenitor cells may be involved in the pathogenesis of human mature B-cell lymphomas.

Kirchhofer D, Vucic D
Protease activity of MALT1: a mystery unravelled.
Biochem J. 2012; 444(2):e3-5 [PubMed] Related Publications
Constitutive NF-κB (nuclear factor κB) activation in B-cell lymphomas relies greatly on the CARMA1 [CARD (caspase recruitment domain)-containing MAGUK (membrane-associated guanylate kinase) 1]-Bcl10-MALT1 (mucosa-associated lymphoid tissue translocation gene 1) signalling complex. Within this protein complex, MALT1 possesses a rather unique enzymatic activity, which allows it to cleave Bcl10, RelB and CYLD, among other substrates. The catalytic activity of MALT1 promotes activation of canonical and non-canonical NF-κB as well as other signalling pathways. However, even after a decade of intense research on MALT1, many mechanistic aspects of its enzymatic activity remain elusive. A recent article by Hachmann, Snipas, van Raam, Cancino, Houlihan, Poreba, Kasperkiewicz, Drag and Salvesen [(2012) Biochem. J. 443, 287-295] provides novel insight into the activation mechanism and the substrate specificity of MALT1. These intriguing findings convincingly demonstrate the importance of MALT1 dimerization for its catalytic activity and pave the way for novel therapeutic approaches that target this crucial regulator of lymphoma survival and proliferation.

van Maldegem F, Wormhoudt TA, Mulder MM, et al.
Chlamydia psittaci-negative ocular adnexal marginal zone B-cell lymphomas have biased VH4-34 immunoglobulin gene expression and proliferate in a distinct inflammatory environment.
Leukemia. 2012; 26(7):1647-53 [PubMed] Related Publications
Ocular adnexal marginal zone B-cell lymphomas (OAMZLs) arise in the connective tissues of the orbit or in the mucosa-associated lymphoid tissue of the conjunctiva. Here, we present the immunological and genetic analyses of 20 primary Chlamydia psittaci (Cp)-negative OAMZLs. Analysis of the immunoglobulin variable heavy chain (IgV(H)) gene usage demonstrated a significant preference for V(H)4-34. A combined analysis across all previously published OAMZLs confirmed that this is a general feature of OAMZL, in particular of the Cp-negative group. Our series of OAMZLs did not express the characteristic rheumatoid factor V(H)DJ(H) rearrangements that were previously found in salivary gland- and gastric-marginal zone B-cell lymphomas (MZBCLs). We did not detect the MZBCL-specific chromosomal translocations, t(11;18) API2-MALT1 (mucosa-associated lymphoid tissue1) and t(14;18) IgH/MALT1. Two cases contained a premature stop codon in the A20 gene (TNFAIP3) and one case harbored the activating MYD88 hotspot mutation L265P. Variable nuclear expression of BCL10, NFκB1 (p50) and NFκB2 (p52) suggests that other additional genetic abnormalities affecting the NFκB pathway exist within this group of lymphomas. OAMZL showed variable expression of the chemokine receptor CXCR3 and integrin α4β7 by the tumor B cells, and low interferon-γ and interlukin-4 mRNA levels in the tissue, indicative of an inflammatory environment with features in between those previously found in cutaneous and other extranodal MZBCL. The strongly biased usage of V(H)4-34 in Cp-negative OAMZLs suggests involvement of a particular stimulatory (auto-) antigen in their development.

Kominato S, Nakayama T, Sato F, et al.
Characterization of chromosomal aberrations in thymic MALT lymphoma.
Pathol Int. 2012; 62(2):93-8 [PubMed] Related Publications
Mucosa-associated lymphoid tissue (MALT) lymphoma arising in the thymus is a rare disorder that shows a strong association with autoimmune disease. Several MALT-lymphoma-specific and -associated chromosomal abnormalities, including t(11;18), t(14;18), t(1;14), trisomy 3 and trisomy 18, are known to occur. The former translocation results in apoptosis inhibitor 2 gene (API2)-MALT lymphoma-associated translocation 1 (MALT1) fusion. In this study, we examined 14 cases of thymic MALT lymphomas for API2-MALT1 fusion using multiplex reverse transcription polymerase chain reaction and looked for trisomy 3, trisomy 18 and abnormalities of MALT1 and IGH genes using fluorescence in situ hybridization. Thymic MALT lymphoma cases had a high frequency of trisomy 3 (7/14 cases), a very low incidence of trisomy 18 (1/14) and no detectable MALT1-associated (0/13) or IGH-associated (0/13) gene abnormalities including t(11;18). A review of the literature showed that the pattern of chromosomal aberrations in thymic MALT lymphoma was similar to those of thyroid and salivary gland MALT lymphomas. Although frequently detected, trisomy 3 was not associated with any of the clinicopathological factors analyzed, suggesting that trisomy 3 may play a role in lymphoma development. In conclusion, the present study showed that thymic MALT lymphoma has a characteristic pattern of chromosomal aberrations that may be similar to those of other autoimmune-associated MALT lymphomas.

Knower KC, To SQ, Takagi K, et al.
Melatonin suppresses aromatase expression and activity in breast cancer associated fibroblasts.
Breast Cancer Res Treat. 2012; 132(2):765-71 [PubMed] Related Publications
The main biological active substance secreted by the pineal gland, melatonin (MLT), counteracts the effects of estrogens in breast cancer via exerting a number of its own oncostatic properties. Recent studies of postmenopausal women have identified that the major metabolite of MLT is statistically significantly associated with a lower risk of developing breast cancer. While MLT production decreases with age, breast cancer risk, however, increases with age and obesity. We hypothesize that MLT inhibits estrogen production in breast adipose fibroblasts (BAFs), the main local source of estrogen in breast tumors of postmenopausal women, by inhibiting transcription of the CYP19A1 gene that encodes the key enzyme aromatase. Normal BAFs were cultured from women undergoing breast reduction surgery, while breast cancer-associated fibroblasts (CAFs) were isolated from three women with estrogen receptor (ER) positive invasive ductal carcinomas. MTNR1A and MTNR1B receptor expression and CYP19A1 mRNA expression following MLT treatments were determined by qRT-PCR. BAFs express the G-protein coupled MLT receptors MTNR1A and MTNR1B with elevated levels of MTNR1A found in CAFs. Treatment of BAFs and CAFs with MLT resulted in significant suppression of CYP19A1 transcription and aromatase activity at pharmacological, physiological and sub-physiological concentrations. MLT suppression occurred through promoter-specific PI.4-, PI.3- and PII-derived CYP19A1 mRNA. Stimulation of CYP19A1 PII-mRNA and aromatase activity by prostaglandin E(2) (PGE(2)) were significantly attenuated by physiological doses of MLT. Lower levels of MLT in aging women may increase the risk of progressing ER-positive breast cancer through a decreased ability to suppress CYP19A1 expression and subsequent local estrogen production in BAFs/CAFs.

Bi Y, Zeng N, Chanudet E, et al.
A20 inactivation in ocular adnexal MALT lymphoma.
Haematologica. 2012; 97(6):926-30 [PubMed] Free Access to Full Article Related Publications
Recent studies showed A20 inactivation by deletion, mutation and promoter methylation in ocular adnexal mucosa-associated lymphoid tissue lymphoma. However, the incidences of A20 abnormalities and their clinical impact remain for the most part unknown. It is also unknown whether ABIN-1 and ABIN-2, the components of the A20 NF-κB inhibitor complex, are inactivated by genetic changes in ocular adnexal mucosa-associated lymphoid tissue lymphoma. A total of 105 cases were investigated for A20 mutation/deletion, ABIN-1/2 mutation, MALT1 and IGH involved translocation. Somatic mutation was seen frequently in A20 (28.6%) but rarely in ABIN-1 (1%) and ABIN-2 (1%). A20 mutations were significantly associated with A20 heterozygous deletion, and both were mutually exclusive from the MALT1 or IGH involved translocations. A20 mutation/deletion was also significantly associated with increased expression of the NF-κB target genes CCR2, TLR6 and BCL2. The cases with A20 mutation/deletion required significantly higher radiation dosages to achieve complete remission than those without these abnormalities.

Hailfinger S, Nogai H, Pelzer C, et al.
Malt1-dependent RelB cleavage promotes canonical NF-kappaB activation in lymphocytes and lymphoma cell lines.
Proc Natl Acad Sci U S A. 2011; 108(35):14596-601 [PubMed] Free Access to Full Article Related Publications
The protease activity of the paracaspase Malt1 contributes to antigen receptor-mediated lymphocyte activation and lymphomagenesis. Malt1 activity is required for optimal NF-κB activation, but little is known about the responsible substrate(s). Here we report that Malt1 cleaved the NF-κB family member RelB after Arg-85. RelB cleavage induced its proteasomal degradation and specifically controlled DNA binding of RelA- or c-Rel-containing NF-κB complexes. Overexpression of RelB inhibited expression of canonical NF-κB target genes and led to impaired survival of diffuse large B-cell lymphoma cell lines characterized by constitutive Malt1 activity. These findings identify a central role for Malt1-dependent RelB cleavage in canonical NF-κB activation and thereby provide a rationale for the targeting of Malt1 in immunomodulation and cancer treatment.

McAllister-Lucas LM, Baens M, Lucas PC
MALT1 protease: a new therapeutic target in B lymphoma and beyond?
Clin Cancer Res. 2011; 17(21):6623-31 [PubMed] Free Access to Full Article Related Publications
The identification of mucosa-associated lymphoid tissue lymphoma translocation 1 (MALT1) as a gene that is perturbed in the B-cell neoplasm MALT lymphoma, already more than a decade ago, was the starting point for an intense area of research. The fascination with MALT1 was fueled further by the observation that it contains a domain homologous to the catalytic domain of caspases and thus, potentially, could function as a protease. Discoveries since then initially revealed that MALT1 is a key adaptor molecule in antigen receptor signaling to the transcription factor NF-κB, which is crucial for lymphocyte function. However, recent discoveries show that this function of MALT1 is not restricted to lymphocytes, witnessed by the ever-increasing list of receptors from cells within and outside of the immune system that require MALT1 for NF-κB activation. Yet, a role for MALT1 protease activity was shown only recently in immune signaling, and its importance was then further strengthened by the dependency of NF-κB-addicted B-cell lymphomas on this proteolytic activity. Therapeutic targeting of MALT1 protease activity might, therefore, become a useful approach for the treatment of these lymphomas and, additionally, an effective strategy for treating other neoplastic and inflammatory disorders associated with deregulated NF-κB signaling.

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