Epidemiology and environmental aspects of marginal zone lymphomas

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue of the ileum in an adult presenting with intussusception: a case report and literature review

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (EMZL), also known as MALT lymphoma, is an extranodal multiorgan-invasive proliferative lymphoma composed of small B cells with variable morphology. It most commonly occurs in the digestive tract, with a high prevalence in the stomach, but EMZL originating in the small intestine is rare and lacks specificity in clinical manifestations, which makes it easy to be misdiagnosed. Herein, we report a rare case of small intestinal EMZL presentation as intussusception in a 32-year-old man. A colonoscopy performed at the local hospital revealed a pedicled polyp about 5 cm × 5 cm in size with a rough surface, and hyperemia was seen in the ileocecal region. He was admitted to our hospital for a polypectomy. A contrast-enhanced computed tomographic (CT) scan suggested ileocolic intussusception, which was subsequently confirmed by a colonoscopy in our hospital. Adult intussusception is relatively rare, with 90% of cases having a known causative mechanism and 40% of cases caused by primary or secondary malignancies. Therefore, we performed a laparoscopic-assisted right hemicolectomy for the patient. The resected specimen showed that the terminal ileum was intussuscepted into the ascending colon, and the intussusception was hyperemia and edema. A 2.5 cm × 2.5 cm × 1.5 cm mass was seen at the end of the intussusception. Postoperative pathology revealed that the mass was EMZL, partially transformed into a large B-cell lymphoma. The patient was transferred to the hematology department and completed a PET-CT showing postoperative manifestations of primary intestinal lymphoma, Lugano staging IE2. Although EMZL was an indolent lymphoma and the patient was in the early stages, the rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) regimen was given in view of the histological transformation. The patient is in regular follow-up. This was a rare case of small intestinal mass due to EMZL presented as intussusception in adults, which highlighted laparoscopic-assisted enterectomy as a potential therapeutic approach in the multidisciplinary collaborative therapy of small intestine EMZL.

Transformation to diffuse large B-cell lymphoma and its impact on survival in patients with marginal zone lymphoma: A population-based study

Some patients with marginal zone lymphoma (MZL) experience histological transformation to diffuse large B-cell lymphoma (DLBCL). Because of the paucity of long-term data on transformation, we conducted a population-based study to estimate the risk of transformation and its impact on survival in MZL. Using the Surveillance, Epidemiology and End Results database, we identified 23 221 patients with histology-proven MZL between 2000 and 2018. Competing risk method, Kaplan-Meier and Cox proportional hazards regression were performed to analyze time-to-event outcomes. Based on 420 events of transformation, the 10-year cumulative incidence rate of transformation is 2.23% (95% CI: 2.00%-2.46%) in MZL, 1.5% (95% CI: 1.3%-1.8%), 2.7% (95% CI: 2.3%-3.2%) and 5.8% (95% CI: 4.6%-7.1%) in extranodal, nodal and splenic MZL (EMZL, NMZL and SMZL), respectively. Patients with SMZL (subdistribution hazard ratio [SHR], 2.96; 95% CI: 2.21-3.96) or NMZL (SHR, 1.49; 95% CI: 1.17-1.90) have a higher risk of transformation than those with EMZL. For each MZL subtype, patients with transformation had a significantly shorter overall survival. Patients with transformation >18 months since MZL diagnosis had longer OS than those who presented within 18 months (5-year rate, 87.4% [95% CI: 83.7%-91.2%] vs 47.9% [95% CI: 38.8%-59.0%]; P < .001). Compared to patients with matched de novo DLBCL, those whose DLBCL was transformed from MZL had a shorter OS (5-year rate, 56.6% [95% CI: 51.9%-61.8%] vs 46.1% [95% CI: 40.9%-51.9%]; P < .001). We concluded that patients with SMZL had the highest risk of transformation. Regardless of MZL subtype, transformation resulted in significantly increased mortality.

Histological criteria for selecting patients who need clonality test for non-gastric MALT lymphoma diagnosis

The histological diagnosis of extranodal marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) is difficult for pathologists. Recently, digital pathology systems have been widely used to provide tools that can objectively measure lesions on slides. In this study, we measured the extent of marginal zone expansion in suspected MALT lymphoma cases and compared the results with those of a molecular clonality test. In total, 115 patients who underwent an IGH gene rearrangement test for suspected MALT lymphoma were included in this study. All cases were histologically classified into three patterns; "small lymphoid aggregates with no germinal center (Pattern 1)," "lymphoid follicles with germinal center (Pattern 2)" and " fused marginal zone or diffuse small lymphocytic proliferation (Pattern 3)." The proportions of monoclonality in Pattern 1, 2, and 3 were 25.0%, 55.0%, and 97.9%, respectively. The ratios of marginal zone thickness to germinal center diameter and entire lymphoid follicle area to germinal center area were measured in Pattern 2 cases using a digital pathology system. Combining the width cutoff of 1.5 and the areal cutoff of 3.5, the sensitivity, specificity, positive predictive value, and negative predictive value for MALT lymphoma were 96.97%, 70.37%, 80.00%, and 95.00%, respectively. In conclusion, through objective measurement of the marginal zone, suspected cases of MALT lymphoma requiring a molecular clonality test can be effectively selected.

Marginal zone lymphoma with severe rashes: A case report

BACKGROUND

Marginal zone lymphoma (MZL) is an indolent subtype of non-Hodgkin lymphoma (NHL), which is rare clinically with severe rashes as the initial symptom.

CASE SUMMARY

This study reports a case of MZL with generalized skin rashes accompanied by pruritus and purulent discharge. First-line treatment with rituximab combined with zanubrutinib had poor effects. However, after switching to obinutuzumab combined with zanubrutinib, the case was alleviated, and the rashes disappeared.

CONCLUSION

For patients with advanced stage MZL not benefiting from type I anti-CD20 monoclonal antibody (mAb) combination therapy, switching to a type II anti-CD20 mAb combination regimen may be considered. This approach may provide a new perspective in the treatment of MZL.

Marginal zone lymphoma: 2023 update on diagnosis and management

DISEASE OVERVIEW

Marginal zone lymphomas (MZL) are collectively the second most common type of indolent lymphoma.

DIAGNOSIS

Three subtypes of MZL are recognized: splenic, extranodal, and nodal. The diagnosis is secured following biopsy of an involved nodal or extranodal site demonstrating a clonal B-cell infiltrate with CD5 and CD10 negative immunophenotype most common. Some cases will features IgM paraprotein, but MYD88 L256P mutations are less frequent than in Waldenstrom macroglobulinemia. Prognostication Several prognostic models have been developed, including the MALT-IPI and the MZL-IPI. The latter is broadly applicable across MZL subtypes and incorporates elevated serum LDH, anemia, lymphopenia, thrombocytopenia and nodal or disseminated subtypes as independent predictors of outcome.

TREATMENT

We discuss suggested approach to therapy for both early and advanced-stage disease, with reference to chemo-immunotherapy, radiotherapy, and emerging treatments in relapsed/refractory disease such as BTK inhibitors.

Management of Marginal Zone Lymphoma: A Canadian Perspective

Marginal zone lymphomas (MZL) are a rare, heterogenous group of lymphomas, accounting for 5-17% of indolent non-Hodgkin lymphomas in the western world. They can be further divided into three subtypes: extranodal MZL, splenic MZL, and nodal MZL. These subtypes differ in clinical presentation and behavior, which influences how they are managed. There is currently no standard of care for the treatment of MZL, owing to the difficulty in conducting phase 3 randomized trials in MZL, and the fact that there are limited data on the efficacy of therapy in individual subtypes. Treatment practices are thus largely borrowed from other indolent lymphomas and are based on patient and disease characteristics, as well as access to therapy. This review summarizes the Canadian treatment landscape for MZL and how these therapies may be sequenced in practice.

Management of indolent B-cell Lymphomas: A review of approved and emerging targeted therapies

The indolent B-cell non-Hodgkin lymphomas (B-NHL) comprise a heterogenous group of lymphoproliferative disorders characterized by slow growth kinetics and a relapsing/remitting course. Management has, until recently, been uniform across all indolent B-NHL subtypes. Improving insight into pathophysiological and molecular features of each disease has led to development of several targeted therapies. Consequently, each subtype must now be considered an individual entity. In this review, we consider the three commonest indolent B-NHLs: follicular lymphoma, marginal zone lymphoma and Waldenstrom's macroglobulinemia and review in detail the data on approved and emerging targeted therapeutic agents for each B-NHL subtype.

Role of Notch2 pathway in mature B cell malignancies

In recent decades, the Notch pathway has been characterized as a key regulatory signaling of cell-fate decisions evolutionarily conserved in many organisms and different tissues during lifespan. At the same time, many studies suggest a link between alterations of this signaling and tumor genesis or progression. In lymphopoiesis, the Notch pathway plays a fundamental role in the correct differentiation of T and B cells, but its deregulated activity leads to leukemic onset and evolution. Notch and its ligands Delta/Jagged exhibit a pivotal role in the crosstalk between leukemic cells and their environment. This review is focused in particular on Notch2 receptor activity. Members of Notch2 pathway have been reported to be mutated in Chronic Lymphocytic Leukemia (CLL), Splenic Marginal Zone Lymphoma (SMZL) and Nodal Marginal Zone Lymphoma (NMZL). CLL is a B cell malignancy in which leukemic clones establish supportive crosstalk with non-malignant cells of the tumor microenvironment to grow, survive, and resist even the new generation of drugs. SMZL and NMZL are indolent B cell neoplasms distinguished by a distinct pattern of dissemination. In SMZL leukemic cells affect mainly the spleen, bone marrow, and peripheral blood, while NMZL has a leading nodal distribution. Since Notch2 is involved in the commitment of leukemic cells to the marginal zone as a major regulator of B cell physiological differentiation, it is predominantly affected by the molecular lesions found in both SMZL and NMZL. In light of these findings, a better understanding of the Notch receptor family pathogenic role, in particular Notch2, is desirable because it is still incomplete, not only in the physiological development of B lymphocytes but also in leukemia progression and resistance. Several therapeutic strategies capable of interfering with Notch signaling, such as monoclonal antibodies, enzyme or complex inhibitors, are being analyzed. To avoid the unwanted multiple "on target" toxicity encountered during the systemic inhibition of Notch signaling, the study of an appropriate pharmaceutical formulation is a pressing need. This is why, to date, there are still no Notch-targeted therapies approved. An accurate analysis of the Notch pathway could be useful to drive the discovery of new therapeutic targets and the development of more effective therapies.

Rituximab plus cladribine versus R-CHOP in frontline management of marginal zone lymphoma in China: a propensity-score matched multicenter study

Marginal zone lymphoma (MZL) is an uncommon subtype of non-Hodgkin lymphoma (NHL). Combination of rituximab and cladribine (R-2CdA) is a potential option for indolent NHL (iNHL) and mantle cell lymphoma (MCL) patients. The goal of this multicenter retrospective study was to assess the efficacy and safety of R-2CdA in MZL to support consensus-reaching in first-line therapy in advanced-stage patients. We searched electronic medical records databases of eight centers in China. Between November 2014 and December 2019, 183 symptomatic advanced MZL patients (42 treated with R-2CdA and 141 with rituximab plus cyclophosphamide, adriamycin, vincristine, and prednisone [R-CHOP]) were identified. After propensity score matching (PSM) (1:1) to adjust for clinical characteristics, 39 patients from each treatment arm were selected. The overall response rate (ORR) (84.6% vs. 94.9%, P = 0.263) and complete response rate (59.0% vs. 66.7%, P = 0.487) were comparable between two protocols. Neither progression-free survival (PFS), including the 5-year PFS (67.7% vs. 56.1%, P = 0.352), nor overall survival was improved by R-2CdA versus R-CHOP. However, R-2CdA was more tolerable than R-CHOP in MZL patients regarding grade 3/4 hematological adverse events (odds ratio [OR] 0.565, 95% confidence interval [CI] neutropenic fever (OR 0.795, 95% CI 0.678-0.932), and infections (OR 0.800, 95% CI 0.640-1.000). Overall, our study demonstrated that R-2CdA is potentially as effective as but safer than R-CHOP in advanced MZL.

The Effect of the Tumor Microenvironment on Lymphoid Neoplasms Derived from B Cells

Lymphomas are characteristic tumors surrounded by an inflammatory microenvironment. The cells of the microenvironment are essential for the growth and survival of neoplastic cells and are recruited through the effect of cytokines/chemokines. Lymphomas include heterogeneous groups of neoplasms infiltrating various lymphoid structures which may arise from B lymphocytes, T lymphocytes, and natural killer (NK) cells at various stages of their differentiation state. In this review article, we analyze the literature data concerning the involvement of the tumor microenvironment (TME) in the progression of lymphomas and the recent advances in the analysis of microenvironment components in the most common forms: some mature B cell lymphoma neoplasms and classic Hodgkin lymphomas. The complex crosstalk between the TME and tumor cells led to the discovery of many mechanisms usable as molecular-targeted therapy through the control of diverse elements of the TME, varying from inhibitors of angiogenic cytokines and their receptors to the regulation of cells' activities and the novel immune checkpoint inhibitors.

A single-center analysis of patients with extranodal marginal zone lymphoma of the breast

Breast extranodal marginal zone lymphoma (EMZL) is a rare malignancy. We performed the largest published to date single-center retrospective analysis of 13 patients with breast EMZL focusing on clinical characteristics and treatment-related outcomes. The rarity of this disease at our center was concordant with the prevalence reported in the literature, with breast EMZL comprising 2% of 654 MZL cases. Most patients presented with stage I-II disease however four (30.8%) patients had stage IV disease mostly due to occult bone marrow (BM) involvement. Interestingly, EMZL was frequently non-FDG avid (66.7%) on staging PET/CT. With a median follow-up of 3.1 years (range 5 months to 10.2 years), the 3-year progression free survival was 68.7% (95%CI 30.2%-88.9%) and overall survival 80.2% (95%CI 40.3%-94.8%). No patient experienced higher-grade transformation. Herein we show that localized breast EMZL can be effectively treated with radiation therapy providing long term disease control.

The Genetic Landscape of Ocular Adnexa MALT Lymphoma Reveals Frequent Aberrations in NFAT and MEF2B Signaling Pathways

A comprehensive constellation of somatic non-silent mutations and copy number (CN) variations in ocular adnexa marginal zone lymphoma (OAMZL) is unknown. By utilizing whole-exome sequencing in 69 tumors we define the genetic landscape of OAMZL. Mutations and CN changes in CABIN1 (30%), RHOA (26%), TBL1XR1 (22%), and CREBBP (17%) and inactivation of TNFAIP3 (26%) were among the most common aberrations. Candidate cancer driver genes cluster in the B-cell receptor (BCR), NFkB, NOTCH and NFAT signaling pathways. One of the most commonly altered genes is CABIN1, a calcineurin inhibitor acting as a negative regulator of the NFAT and MEF2B transcriptional activity. CABIN1 deletions enhance BCR-stimulated NFAT and MEF2B transcriptional activity, while CABIN1 mutations enhance only MEF2B transcriptional activity by impairing binding of mSin3a to CABIN1. Our data provide an unbiased identification of genetically altered genes that may play a role in the molecular pathogenesis of OAMZL and serve as therapeutic targets.

Bacterial Infection and Non-Hodgkin B-Cell Lymphoma: Interactions between Pathogen, Host and the Tumor Environment

Non-Hodgkin B-cell lymphomas (NHL) are a heterogeneous group of lymphoid neoplasms with complex etiopathology, rich symptomatology, and a variety of clinical courses, therefore requiring different therapeutic approaches. The hypothesis that an infectious agent may initiate chronic inflammation and facilitate B lymphocyte transformation and lymphogenesis has been raised in recent years. Viruses, like EBV, HTLV-1, HIV, HCV and parasites, like Plasmodium falciparum, have been linked to the development of lymphomas. The association of chronic Helicobacter pylori (H. pylori) infection with mucosa-associated lymphoid tissue (MALT) lymphoma, Borrelia burgdorferi with cutaneous MALT lymphoma and Chlamydophila psittaci with ocular adnexal MALT lymphoma is well documented. Recent studies have indicated that other infectious agents may also be relevant in B-cell lymphogenesis such as Coxiella burnettii, Campylobacter jejuni, Achromobacter xylosoxidans, and Escherichia coli. The aim of the present review is to provide a summary of the current literature on infectious bacterial agents associated with B-cell NHL and to discuss its role in lymphogenesis, taking into account the interaction between infectious agents, host factors, and the tumor environment.

Risk and survival of second primary malignancies following diagnosis of gastric mucosa-associated lymphoid tissue lymphomas: A population-based study

Whether gastric mucosa-associated lymphoid tissue lymphoma (GML) is associated with a higher risk of second primary malignancy (SPM) remains controversial. This study aimed to evaluate the detailed risk of SPM and its prognosis in patients with GML based on a large population-based cohort. The Surveillance, Epidemiology, and End Results database was searched to identify patients who were diagnosed with GML during 2000-2014. The standardized incidence ratio was used to estimate the relative risk of developing SPM. Overall survival was evaluated using the Kaplan-Meier method with the log-rank test, as well as Cox regression analysis. Among 3,379 patients with GML, 416 patients (12.31%) developed SPMs. Compared to the general US population, GML patients had a significantly increased risk of developing SPM (standardized incidence ratio: 1.46, 95% CI: 1.33-1.61). The SPM sites were stomach, lung and bronchus, small intestine, thyroid, mouth, and non-Hodgkin's lymphoma. The risk of developing SPM in GML patients varied according to clinical and demographic characteristics. Patients with younger age (<50 year), chemotherapy use and radiotherapy use had the higher risk of developing SPMs. Relative to patients with only GML, GML patients who developed the SPMs had significantly poorer overall survival (P < 0.001). Among GML patients with SPMs, poor overall survival was independently associated with non-localized SPM disease, shorter latency period (<60 months), chemotherapy use and older age (≥70 year). Patients with GML had an elevated risk of developing SPM, which was associated with a poor prognosis. These findings may be useful for improving follow-up surveillance for patients with GML.

Radiotherapy in Early-stage Gastric MALT: Improved Survival Without Increased Cardiac Death

PURPOSE

Radiotherapy (RT) is an effective treatment for localized gastric mucosa-associated lymphoid tissue (MALT) lymphomas unresponsive to antibiotic therapy; however, irradiating the stomach can result in significant radiation to the heart, a risk factor for cardiac disease. We analyzed the Surveillance, Epidemiology, and End Results database to evaluate outcomes related to cardiac disease among patients treated with RT for stage I gastric MALT.

MATERIALS AND METHODS

We identified adult patients treated between 1993 and 2014. The relationship between treatment modality (RT, chemotherapy, combination, and no treatment) and overall survival (OS), mucosa-associated lymphoid tissue-specific survival (MSS), non-mucosa-associated lymphoid tissue-specific survival (non-MSS), and cardiac-specific survival (CSS) was assessed using the Kaplan-Meier estimator and Cox proportional hazards analyses.

RESULTS

A total of 2996 patients (median follow-up, 5.6 y) were analyzed: 27.5% had received RT alone, 12.1% chemotherapy alone, 3.9% chemoradiotherapy, and 56.5% no/unknown treatment (including antibiotic therapy). Compared with RT alone, patients who received chemotherapy alone exhibited worse OS (hazard ratio [HR]: 1.67; 95% confidence interval [CI]: 1.32-2.10; P<0.001) and MSS (HR: 2.10; 95% CI: 1.36-3.23; P=0.001). Although CSS appeared worse in patients who received chemotherapy (HR: 1.56; 95% CI: 0.92-2.66; P=0.10), it was not statistically significant. When comparing orbital and gastric MALT patients, there was no significant difference in CSS (HR: 0.80; 95% CI: 0.49-1.31; P=0.38).

CONCLUSIONS

RT improved survival among patients with stage I gastric MALT without increasing the risk of cardiac death. Those with gastric MALT exhibited similar CSS to those with orbital MALT. Although we cannot analyze nonfatal cardiac toxicity, these results suggest that, absent antibiotic therapy, RT should remain first-line treatment for early-stage gastric MALT.

Demographical and Clinical Features of Marginal Zone Lymphomas: A Retrospective Study of Turkish Oncology Group (TOG)

Marginal zone lymphomas (MZLs) are rare and indolent subtypes of non-Hodgkin lymphomas, and their clinical behaviours are heterogeneous. The aim of this study was to evaluate the clinical and prognostic characteristics of MZL. In this multicentre retrospective study, we analyzed demographical, clinical and prognostic features of 64 MZL patients. The median age was 54.0 and 78.1% of the patients had extra-nodal disease at presentation. Most of the patients were treated with chemotherapy. The 5 years and 10 years overall survival (OS) rates were 74.5% and 62.1%, respectively. The analysis of factors associated with OS showed that ECOG performance score was an important prognostic factor, with 133.0 months (95% CI 49.3-216.5) versus 18.0 months (95% CI 12.1-23.7) for ECOG 0-1 and 2-3, respectively (p = 0.011). Prognosis of MZL is favorable and ECOG performance score was found associated with OS. Further detailed studies with large patient numbers are needed to clarify the clinical features and treatment management of MZLs.

Front-line management of indolent non-Hodgkin lymphoma in Australia. Part 2: mantle cell lymphoma and marginal zone lymphoma

Mantle cell lymphoma (MCL) and the marginal zone lymphoma (MZL) subtypes (nodal MZL, extra-nodal MZL of mucosa-associated lymphoid tissue (MALT lymphoma) and splenic MZL) are uncommon lymphoma subtypes, accounting for less than 5-10% of all non-Hodgkin lymphoma. The evidence base for therapy is therefore limited and enrolment into clinical trials is preferred. Outcomes for patients with MCL have been steadily improving mainly due to the adoption of more intense strategies in younger patients, the use of rituximab maintenance and the recent introduction of bendamustine in older patients. MZL is a more heterogeneous group of cancer with both nodal, extra-nodal and splenic subtypes. Extranodal MZL may be associated with autoimmune or infectious aetiologies, and can respond to eradication of the causative pathogen. Proton pump inhibitor plus dual antibiotics in Helicobacter pylori positive gastric MALT lymphoma is curative in many patients. Watchful waiting is appropriate in most patients with asymptomatic advanced stage disease, which tends to behave in a particularly indolent manner. Other options for symptomatic disease include splenectomy, chemoimmunotherapy with rituximab and, more recently, targeted therapies.

Marginal Zone Lymphoma: State-of-the-Art Treatment

OPINION STATEMENT

Despite being the second most common indolent non-Hodgkin's lymphoma (iNHL), marginal zone lymphoma (MZL) remains largely understudied, and given its underlying disease heterogeneity, it is challenging to define a single treatment approach for these patients. For localized disease, local therapy is recommended such as triple therapy for H. pylori in gastric extranodal MZL, splenectomy for splenic MZL, and radiotherapy for nodal MZL. For disseminated disease with low tumor burden, a watch and wait or single-agent rituximab can be used. However, for symptomatic disease, a similar approach to follicular lymphoma (FL) can be used with chemoimmunotherapy approaches such as bendamustine and rituximab. High FDG uptake is not common in MZL and is not diagnostic by itself of transformation to high-grade lymphoma but informs the choice of the site to be biopsied. Transformation into a large B cell lymphoma is treated with R-CHOP-like regimens. Patients with relapsing disease after at least one CD20-based therapy have several recently approved chemotherapy-free options including B cell receptor inhibitors such ibrutinib (approved specifically in MZL) and immunomodulatory agents such as lenalidomide and rituximab (FDA approved in MZL and FL). Phosphoinositide 3-kinase (PI3K) inhibitors have shown excellent activity in iNHL, specifically in MZL, with breakthrough designation status for copanlisib and umbralisib, allowing off label use of this class of agents in clinical practice. With the availability of prospective clinical trials using chemo-free approaches, specifically those targeting abnormal signaling pathways activated in MZL tumors and its microenvironment, treating physicians are encouraged to enroll patients on these clinical trials in order to better understand the underlying biology, mechanisms of response, and resistance to current therapies and help design future rationale combination strategies.

Short survival and frequent transformation in extranodal marginal zone lymphoma with multiple mucosal sites presentation

Between 11 and 37% of extranodal marginal zone lymphoma (EMZL) patients present with disease involvement in multiple mucosal sites (MMS). We analyzed 405 EMZL patients seen between 1995 and 2017: 265 (65.4%) patients presented with stage I disease, 49 of 309 (15.8%) patients with bone marrow involvement, and 35 of 328 (10.7%) patients with monoclonal gammopathy (MG). Forty-three (10.6%) patients had MMS presentation, which was more frequently seen in patients aged >60 years (55.8%). Five (17.9%) of 28 MMS patients had MG. MMS patients commonly exhibited the International Prognostic Index (IPI) >2 (79.1%), Follicular Lymphoma International Prognostic Index (FLIPI) >2 (39.5%), and Mucosa-Associated Lymphoid Tissue Lymphoma International Prognostic Index (MALT-IPI) 2-3 (60.5%). Both MMS presentation and MG were associated with shorter survival univariately. In multivariable Cox regression models, shorter progression-free survival (PFS) and overall survival (OS) were observed in patients with MMS (hazard ratio [HR] = 3.08 and 2.92, respectively), age ≥60 years (HR = 1.52 and 2.45, respectively), and in patients who failed to attain a complete remission following initial therapy (HR = 3.27 and 2.13, respectively). Elevated lactate dehydrogenase was associated with shorter PFS (HR = 1.92), while anemia (HR = 2.46) was associated with shortened OS. MALT-IPI ≥2 (HR = 2.47 and 4.75), FLIPI >2 (HR = 1.65 and 2.09), and IPI >2 (HR = 2.09 and 1.73) were associated with shorter PFS and OS, respectively. Higher grade transformation (HGT) occurred in 11 (25.6%) MMS patients with a 5-year cumulative incidence of 13.2% (95% CI 4.7-26.1%). EMZL patients with MMS presentation represent a novel clinical subset associated with shorter PFS, OS, and higher incidence of HGT that needs novel therapeutic approaches.

The NOTCH Pathway and Its Mutations in Mature B Cell Malignancies

The systematic application of next-generation sequencing to large cohorts of oncologic samples has opened a Pandora's box full of known and novel genetic lesions implicated in different steps of cancer development and progression. Narrowing down to B cell malignancies, many previously unrecognized genes emerged as recurrently mutated. The challenge now is to determine how the mutation in a given gene affects the biology of the disease, paving the way to functional genomics studies. Mutations in NOTCH family members are shared by several disorders of the B series, even if with variable frequencies and mutational patterns. In silico predictions, revealed that mutations occurring in NOTCH receptors, despite being qualitatively different, may have similar effects on protein processing, ultimately leading to enhanced pathway activation. The discovery of mutations occurring also in downstream players, either potentiating positive signals or compromising negative regulators, indicates that multiple mechanisms in neoplastic B cells concur to activate NOTCH pathway. These findings are supported by results obtained in chronic lymphocytic leukemia and splenic marginal zone B cell lymphoma where deregulation of NOTCH signaling has been functionally characterized. The emerging picture confirms that NOTCH signaling is finely tuned in cell- and microenvironment-dependent ways. In B cell malignancies, it contributes to the regulation of proliferation, survival and migration. However, deeper biological studies are needed to pinpoint the contribution of NOTCH in the hierarchy of events driving B cells transformation, keeping in mind its role in normal B cells development. Because of its relevance in leukemia and lymphoma biology, the NOTCH pathway might represent an appealing therapeutic target: the next few years will tell whether this potential will be fulfilled.

Risk Factors for Transformation to Higher-Grade Lymphoma and Its Impact on Survival in a Large Cohort of Patients With Marginal Zone Lymphoma From a Single Institution

PURPOSE

Given the paucity of data on higher-grade transformation (HGT) to aggressive lymphoma in patients with marginal zone lymphoma (MZL), we report on a large cohort of patients, identify risk factors, and determine HGT impact on overall survival (OS).

METHODS

We analyzed 453 patients with biopsy-proven MZL seen at our institution between 1995 and 2016. Kaplan-Meier, Cox proportional hazards regression, and competing risk methods were used in analyses of time-to-event outcomes.

RESULTS

Thirty-four patients (7.5%) had biopsy-proven HGT to diffuse large B-cell lymphoma, including seven (21%) diagnosed at the time of initial MZL diagnosis. Among 27 incident patients, median time to HGT was 29 months (range, 1.3 to 135 months). Higher risk of HGT was observed in those with nodal/splenic MZL (subdistribution hazard ratio [SHR], 2.60; P = .023). On multivariable competing risk analysis, elevated lactate dehydrogenase (SHR, 2.71), more than four nodal sites (SHR, 2.97), and failure to achieve complete remission (CR) after initial treatment (SHR, 3.76) conveyed significantly higher risk for HGT ( P < .02). International Prognostic Index (IPI), Follicular Lymphoma IPI, and Mucosa-Associated Lymphoid Tissue Lymphoma IPI were only significant predictors of HGT univariably. Patients with HGT had shorter OS (5-year rate, 65% v 86%; P < .001). Patients who presented with HGT within 12 months since MZL diagnosis had shorter OS than those with HGT at MZL diagnosis combined with those with HGT more than 12 months later (4-year rate, 43% v 81%, P < .001). Non-CR and higher scores of IPI, Follicular Lymphoma IPI, and Mucosa-Associated Lymphoid Tissue Lymphoma IPI were the main significant predictors for shorter progression-free survival and OS.

CONCLUSION

Failure to achieve CR after initial treatment, elevated lactate dehydrogenase, and more than four nodal sites at the time of MZL diagnosis are the main predictors of increased risk of HGT. Patients with HGT have shorter OS.