Waldenström macroglobulinaemia

Bruton Tyrosine Kinase Inhibition: an Effective Strategy to Manage Waldenström Macroglobulinemia

PURPOSE OF REVIEW

The treatment of Waldenström macroglobulinemia (WM) has evolved over the past decade. With the seminal discoveries of MYD88 and CXCR warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) mutations in WM cells, our understanding of the disease biology and treatment has improved. The development of a new class of agents, Bruton tyrosine kinase inhibitors (BTKi), has substantially impacted the treatment paradigm of WM. Herein, we review the current and emerging BTKi and the evidence for their use in WM.

RECENT FINDINGS

Clinical trials have established the role of covalent BTKi in the treatment of WM. Their efficacy is compromised among patients who harbor CXCR4WHIM mutation or MYD88WT genotype. The development of BTKC481 mutation-mediated resistance to covalent BTKi may lead to disease refractoriness. Novel, non-covalent, next-generation BTKi are emerging, and preliminary results of the early phase clinical trials show promising activity in WM, even among patients refractory to a covalent BTKi. Covalent BTK inhibitors have demonstrated meaningful outcomes in treatment-naïve (TN) and relapsed refractory (R/R) WM, particularly among those harboring the MYD88L265P mutation. The next-generation BTKi demonstrate improved selectivity, resulting in a more favorable toxicity profile. In WM, BTKi are administered until progression or the development of intolerable toxicity. Consequently, the potential for acquired resistance, the emergence of cumulative toxicities, and treatment-related financial burden are critical challenges associated with the continuous therapy approach. By circumventing BTK C481 mutations that alter the binding site to covalent BTKi, the non-covalent BTKi serve as alternative agents in the event of acquired resistance. Head-to-head comparative trials with the conventional chemoimmunotherapies are lacking. The findings of the RAINBOW trial (NCT046152), comparing the dexamethasone, rituximab, and cyclophosphamide (DRC) regimen to the first-generation, ibrutinib are awaited, but more studies are needed to draw definitive conclusions on the comparative efficacy of chemoimmunotherapy and BTKi. Complete response is elusive with BTKi, and combination regimens to improve upon the efficacy and limit the treatment duration are also under evaluation in WM.

Differential Diagnosis and Therapeutic Advances in Multiple Myeloma: A Review Article

Multiple myeloma (MM) is a hematologic malignancy characterized by the abnormal clonal proliferation of plasma cells that may result in focal bone lesions, renal failure, anemia, and/or hypercalcemia. Recently, the diagnosis and treatment of MM have evolved due to a better understanding of disease pathophysiology, improved risk stratification, and new treatments. The incorporation of new drugs, including proteasome inhibitors, immunomodulatory drugs, anti-CD38 antibodies and high-dose chemotherapy followed by hematopoietic stem cell transplantation, has resulted in a significant improvement in patient outcomes and QoL. In this review, we summarize differential diagnoses and therapeutic advances in MM.

Multimodal Imaging Characteristics and Risk Factors Analysis of Waldenström Macroglobulinemia Retinopathy

PURPOSE

To summarize the multimodal imaging features and analyze the risk factors of Waldenström macroglobulinemia retinopathy (WMR).

DESIGN

Retrospective, cross-sectional study.

METHODS

Patients diagnosed with WM and underwent ophthalmic examination in Peking Union Medical College Hospital in the last decade were included. Multimodal imaging characteristics of WMR were summarized. Univariate and multivariate logistic regression analysis of WMR and potential systemic and ocular factors was performed.

RESULTS

A total of 50 patients with WM were included in this study, and 28 patients had WMR in at least 1 eye. WMR was found to have worse LogMAR visual acuity (0.52 ± 0.54 vs 0.21 ± 0.18, P = .009) and was characterized by tortuous retinal vessels, extensive retinal hemorrhage, distinctive shape of macular edema, and so on. In univariate analysis, the presence of WMR was significantly associated with the mean visual acuity (LogMAR), serum red blood cell counts, serum platelet counts, hemoglobin level, serum M protein, serum IgM level, and lactate dehydrogenase (with P < .05). In multivariate analysis, WMR was significantly correlated with M protein (adjusted odds ratio = 1.127, 95% CI: 1.052-1.209, P= .001) and serum IgM (adjusted odds ratio = 1.059, 95% CI: 1.023-1.095, P = .001) with the predicted areas under the curve of 0.859 and 0.820, respectively. The optimal cutoff values were 26.2 g/L for M protein and 51.0 g/L for IgM, which accounts for a sensitivity of 95.4% and 95.4% and specificity of 64.3% and 60.7%, respectively.

CONCLUSIONS

WMR has specific characteristics in ophthalmic examinations. Serum IgM levels and M protein are good predictors of WMR, which could attach important value of fundus examinations for patients with WM.

Research Progress of CXCR4-Targeting Radioligands for Oncologic Imaging

C-X-C motif chemokine receptor 4 (CXCR4) plays a key role in various physiological functions, such as immune processes and disease development, and can influence angiogenesis, proliferation, and distant metastasis in tumors. Recently, several radioligands, including peptides, small molecules, and nanoclusters, have been developed to target CXCR4 for diagnostic purposes, thereby providing new diagnostic strategies based on CXCR4. Herein, we focus on the recent research progress of CXCR4-targeting radioligands for tumor diagnosis. We discuss their application in the diagnosis of hematological tumors, such as lymphomas, multiple myelomas, chronic lymphocytic leukemias, and myeloproliferative tumors, as well as nonhematological tumors, including tumors of the esophagus, breast, and central nervous system. Additionally, we explored the theranostic applications of CXCR4-targeting radioligands in tumors. Targeting CXCR4 using nuclear medicine shows promise as a method for tumor diagnosis, and further research is warranted to enhance its clinical applicability.

Beyond monoclonal gammopathy of undetermined significance, clinical spectrum of immunoglobulin M gammopathy: a case series with focus on the diagnostic and management challenges

Immunoglobulin M monoclonal gammopathy is detected in Waldenström macroglobulinemia (WM), a rare lymphoplasmacytic lymphoma with serum immunoglobulin M. We report three rare presentations with focus on diagnostic and management challenges of type I cryoglobulinemia, type II cryoglobulinemia, and Bing-Neel syndrome. In approximately 10% of WM cases, macroglobulins can precipitate to cryoglobulins. Type I and II cryoglobulinemia, representing 10-15% and 50-60% of WM cases, respectively, present with vasculitis and renal failure. Bing-Neel syndrome, representing 1% of WM patients, is a rare neurological complication with lymphoplasmacytic infiltration in the brain. WM diagnosis includes bone marrow biopsy, immunophenotypic analysis, and MYD88 L265P mutation. We initiated management of cryoglobulinemia with dexamethasone, rituximab, and cyclophosphamide; in Bing-Neel, bortezomib and dexamethasone, followed by a Bruton tyrosine kinase inhibitor.

Frontline Management of Waldenström Macroglobulinemia with Chemoimmunotherapy

Despite the introduction of effective novel agents, chemoimmunotherapy (CIT), with its widespread use, retains relevance and is one of the 2 vastly disparate strategies to treat Waldenström macroglobulinemia (WM), the alternative being the Bruton tyrosine kinase inhibitor (BTKi)-based approach. Considerable evidence over the past decades supports the integration of the monoclonal anti-CD20 antibody, rituximab, to the CIT backbone in WM, a CD20+ malignancy. Besides substantial efficacy, the finite duration of the treatment, coupled with lower rates of cumulative and long-term, clinically significant adverse effects and greater affordability, make CIT appealing, notwithstanding the lack of quality-of-life data with such an approach in WM. A phase 3 randomized controlled trial reported substantially higher efficacy and a more favorable safety profile of the bendamustine-rituximab (BR) doublet compared with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) among patients with WM. Subsequent studies reaffirmed its high efficacy and tolerability, making BR the mainstay of managing treatment-naïve patients with WM. High-quality evidence supporting the use of BR over Dexamethasone, Rituximab, and Cyclophosphamide (DRC), another commonly used regimen, is lacking, as is its comparison with the continuous BTKi-based approach. However, DRC appeared less potent than BR in cross-trial comparisons and retrospective series involving treatment-naïve patients with WM. Additionally, a recent retrospective, international study demonstrated comparable outcomes with fixed-duration BR and continuous ibrutinib monotherapy among previously untreated, age-matched patients exhibiting MYD88^L265P mutation. However, unlike ibrutinib, BR appears effective irrespective of the MYD88 mutation status. CIT, preferably BR, is well suited to serve as the control arm (comparator) regimen against which novel targeted agents may be evaluated as frontline therapies for WM in high-quality trials. Purine analog-based CIT has been extensively evaluated in WM, although its use has waned, even in the multiply relapsed patient population, as effective and safer alternatives emerge.

Calculated Globulin as a potential screening tool for paraproteinemia to aid in the early diagnosis of Multiple Myeloma

BACKGROUND

Multiple Myeloma (MM) is a haematological malignancy with increasing global incidence. Diagnosis of MM should be initiated at the primary care level to achieve the best patient outcome. However, this can be delayed due to nonspecific presenting symptoms, such as back pain and fatigue.

OBJECTIVES

The aim of this study was to investigate if commonly requested blood tests could indicate MM in primary care and potentially lead to earlier diagnosis.

DESIGN AND METHODS

This retrospective observational study involved an audit of clinical and laboratory data from 109 MM patients, including patients with Active MM (N=53), Smouldering MM (N=33), and Free light chain MM (N=23).

RESULTS

Of the 16 potential biomarkers investigated, the most promising indicator for early detection of active MM and Smouldering MM was an increased Calculated Globulin (CG). The median CG for patients with active MM (50g/L) was 78.6% higher than the healthy control group (28g/L). Smouldering MM patients had a median CG value (38g/L), which was 35.7% higher than the control group. Of interest, the median CG result was only 16.7% higher in the control group than in the free light chain MM group, suggesting CG would not be as effective at detecting this subtype.

CONCLUSIONS

CG is derived from Total Protein and Albumin data, which are commonly measured in routine liver function profiles, thus there is no additional test or cost requirement. Based on these data, CG has potential as a clinical biomarker to support early detection of MM at the primary care level and allow for appropriate targeted investigations.

Treatment paradigm in Waldenström macroglobulinemia: frontline therapy and beyond

Waldenström macroglobulinemia (WM) is an indolent lymphoplasmacytic lymphoma. Recent strides made in the genomic profiling of patients with WM have led to the identification of many novel therapeutic targets. Patients with WM can present with asymptomatic disease and not all patients require treatment. When criteria for initiating systemic therapy are met, the choice of therapy depends on the tumor genotype (MYD88 and CXCR4 mutation status), patient preference (fixed versus continuous duration therapy, oral versus intravenous route, cost), associated medical comorbidities, and adverse effect profile of the treatment. In the absence of head-to-head comparison between chemoimmunotherapy and Bruton’s tyrosine kinase inhibitors in otherwise fit patients with a MYD88^L265P mutation, our preference is fixed duration therapy with four to six cycles of chemoimmunotherapy with bendamustine–rituximab. In this review, we discuss the role of MYD88 and CXCR4 mutation in treatment selection, and current data for frontline and salvage treatment options in patients with WM.

Blurry Vision as a Presentation of Waldenström's Macroglobulinemia: A Case Report With Review of Current Management

A patient was diagnosed with Waldenström’s macroglobulinemia (WM) after the initial findings of anemia and ophthalmological findings of retinal hemorrhage. Upon further workup, the patient was found to have an IgM predominant monoclonal gammopathy on serum protein electrophoresis (SPEP) and urine protein electrophoresis (UPEP). This highlights the need for open communication between different specialties, streamlining rapid and accurate diagnosis. Also highlighted are the unique pathophysiological changes involved in the development of WM. A patient’s primary complaint was blurry vision. After the patient was noted to have a monoclonal gammopathy on SPEP, bone marrow biopsy was performed. The bone marrow biopsy findings were consistent with lymphoplasmacytic lymphoma (LPL). The patient received plasmapheresis and chemotherapy. The disease course is described. The patient saw rapid improvement in all lab abnormalities after the beginning of the appropriate therapy of plasmapheresis and chemotherapy. Remission is common with WM. Regular follow-up with this patient is important.

Treatment Patterns and Outcomes in a Nationwide Cohort of Older and Younger Veterans with Waldenström Macroglobulinemia, 2006-2019

Simple Summary

Waldenström macroglobulinemia is a rare cancer about which little is known. Evidence from real-world settings provides invaluable information to patients and clinicians, especially for older and/or frailer patients, a demographic often excluded from clinical trials. This study provides information about treatment patterns and outcomes from real-world cohorts of older (>70 years) and younger (≤70 years) patients. We report findings across early (2006–2012) and modern (2013–2019) eras, reflecting a transition during which the number of treatments available for Waldenström macroglobulinemia rapidly increased. We found marked improvements in treatment outcomes among older patients in the modern vs early era, with little or no improvement in outcomes among younger patients. Our findings emphasize the importance of real-world evidence in guiding patient-specific treatment decisions.

Abstract

Little is known about real-world treatment patterns and outcomes in Waldenström macroglobulinemia (WM) following the recent introduction of newer treatments, especially among older adults. We describe patterns of first-line (1 L) WM treatment in early (2006–2012) and modern (2013–2019) eras and report outcomes (overall response rate (ORR), overall survival (OS), progression-free survival (PFS), and adverse event (AE)-related discontinuation) in younger (≤70 years) and older (>70 years) populations. We followed 166 younger and 152 older WM patients who received 1 L treatment between January 2006 and April 2019 in the Veterans Health Administration. Median follow-up was 43.5 months (range: 0.6–147.2 months). Compared to the early era, older patients in the modern era achieved improved ORRs (early: 63.8%, modern: 72.3%) and 41% lower risk of death/progression (hazard ratio (HR) for PFS: 0.59, 95% CI (confidence interval): 0.36–0.95), with little change in AE-related discontinuation between eras (HR: 0.82, 95% CI: 0.4–1.7). In younger patients, the AE-related discontinuation risk increased almost fourfold (HR: 3.9, 95% CI: 1.1–14), whereas treatment effects did not change between eras (HR for OS: 1.4, 95% CI: 0.66–2.8; HR for PFS: 1.1, 95% CI: 0.67–1.7). Marked improvements in survival among older adults accompanied a profound shift in 1 L treatment patterns for WM.

Bing-Neel syndrome: A case reports

INTRODUCTION

Bing-Neel syndrome (BNS) is a rare complication of of Waldenström macroglobulinemia (WM) identified by involvement of central nervous system (CNS) lymphoplasmacytic cells.

CASE REPORT

We present a patient who was diagnosed with Bing-Neel syndrome four years after the diagnosis of Waldenström macroglobulinemia.

MANAGEMENT & OUTCOME

The patient was admitted with neurological symptoms. There were lesions associated with WM involvement on brain imaging. The diagnosis was made by brain biopsy. High dose methotrexate treatment was given.

DISCUSSION

CNS infiltrating agents such as fludarabine, methotrexate and cytarabine are often used in BNS treatment. Ibrutinib, which is a new bruton tyrosine kinase inhibitor, has recently started to be used in BNS treatment, as it has been shown to be effective and penetrate the CNS.

The Non-Coding RNA Landscape of Plasma Cell Dyscrasias

Despite substantial advancements have been done in the understanding of the pathogenesis of plasma cell (PC) disorders, these malignancies remain hard-to-treat. The discovery and subsequent characterization of non-coding transcripts, which include several members with diverse length and mode of action, has unraveled novel mechanisms of gene expression regulation often malfunctioning in cancer. Increasing evidence indicates that such non-coding molecules also feature in the pathobiology of PC dyscrasias, where they are endowed with strong therapeutic and/or prognostic potential. In this review, we aim to summarize the most relevant findings on the biological and clinical features of the non-coding RNA landscape of malignant PCs, with major focus on multiple myeloma. The most relevant classes of non-coding RNAs will be examined, along with the mechanisms accounting for their dysregulation and the recent strategies used for their targeting in PC dyscrasias. It is hoped these insights may lead to clinical applications of non-coding RNA molecules as biomarkers or therapeutic targets/agents in the near future.

Lymphoplasmacytic lymphoma infiltrating both lacrimal glands in a patient with Waldenström's macroglobulinemia

Purpose

To describe a case of Waldenström's macroglobulinemia/lymphoplasmacytic lymphoma with infiltration of both lacrimal glands.

Observations

A 63-year-old male with Waldenström's macroglobulinemia was referred to the ophthalmological clinic due to intermittent bilateral painless swollen eyelids. The patient had slight bilateral chemosis along with swelling of both eyelids. A mechanical ptosis was present on both sides. Funduscopic examination and tonometry were normal. Computed tomography and positron emission tomography showed an enlargement of both lacrimal glands with positive PET signal, and hence a biopsy was performed for histological and cytogenetic examination. Histopathological examination revealed an infiltrate of lymphoplasmacytic cells and small lymphocytes within the lacrimal gland. The tumor cells stained positive for IgM and CD20, CD79, BCL-2, and kappa light chain. A cytogenetic examination revealed a mutation in MYD88 confirming Morbus Waldenström/lymphoplasmacytic lymphoma.

Conclusions and importance

Intermittent swollen lacrimal glands are a rather common symptom, and Morbus Waldenström/lymphoplasmacytic lymphoma should be considered as a differential diagnosis. This symptom should be carefully evaluated in Waldenström patients, as it can be a sign of disease progression in case of lacrimal gland involvement.

Development of Central Nervous System Vasculitis in a Patient with Waldenstrom Macroglobulinemia: A Rare Presentation with Poor Prognosis

Waldenstrom macroglobulinemia (WM) is a rare lymphoproliferative disorder characterized by the presence of monoclonal immunoglobulin M in serum. WM may present with neurologic complications involving the peripheral and central nervous systems (CNS) though CNS complications associated with WM are rare. We present a case of a 72-year-old male with an 18-month history of WM who experienced neurologic and constitutional symptoms indicative of WM progression over a three-week period while on rituximab maintenance therapy. The patient’s symptoms were initially attributed to rituximab-induced asthenia though his clinical condition did not improve with rituximab discontinuation. Due to progressively worsening neurologic symptoms, the patient was re-evaluated and found to have multiple cerebral infarcts and increased serum cryoglobulin levels indicative of cryoglobulinema. The patient was promptly initiated on a combination regimen of high dose steroids, intravenous immunoglobulin (IVIG), and plasmapheresis but had a poor response. Brain biopsy revealed necrotizing vasculitis with dense intra- and peri-vascular CD3 positive T-cell infiltrates with mural necrosis. This is a unique case of WM complicated by type 1 cryoglobulinemia associated with CNS vasculitis that was unresponsive to active rituximab therapy; this case illustrates a poor prognosis of patients with CNS involvement in WM.

CXCR4-targeted PET imaging using 64Cu-AMD3100 for detection of Waldenström Macroglobulinemia

Objective:  Waldenström Macroglobulinemia (WM) is a rare B-cell malignancy characterized by secretion of immunoglobulin M and cancer infiltration in the bone marrow. Chemokine receptor such as CXCR4 and hypoxic condition in the bone marrow play crucial roles in cancer cell trafficking, homing, adhesion, proliferation, survival, and drug resistance. Herein, we aimed to use CXCR4 as a potential biomarker to detect hypoxic-metastatic WM cells in the bone marrow and in the circulation by using CXCR4-detecting radiopharmaceutical.Methods: We radiolabeled a CXCR4-inhibitor (AMD3100) with ⁶⁴Cu and tested its binding to WM cells with different levels of CXCR4 expression using gamma counter in vitro. The accumulation of this radiopharmaceutical tracer was tested in vivo in subcutaneous and intratibial models using PET/CT scan. In addition, PBMCs spiked with different amounts of WM cells ex vivo were detected using gamma counting.Results: In vitro, ⁶⁴Cu-AMD3100 binding to WM cell lines demonstrated a direct correlation with the level of CXCR4 expression, which was increased in cells cultured in hypoxia with elevated levels of CXCR4, and decreased in cells with CXCR4 and HIF-1α knockout. Moreover, ⁶⁴Cu-AMD3100 detected localized and circulating CXCR4^high WM cells with high metastatic potential.Conclusions: In conclusion, we developed a molecularly targeted system, ⁶⁴Cu-AMD3100, which binds to CXCR4 and specifically detects WM cells with hypoxic phenotype and metastatic potential in the subcutaneous and intratibial models. These preliminary findings using CXCR4-detecting PET radiopharmaceutical tracer indicate a potential technology to predict high-risk patients for the progression to WM due to metastatic potential.

How we manage patients with Waldenström macroglobulinaemia

Waldenström macroglobulinaemia (WM) is a rare, indolent B-cell lymphoproliferative disorder characterized by cellular involvement in bone marrow and monoclonal IgM production. Symptoms can be related to cytopenias, tumoural involvement, or IgM-related disorders. Somatic mutations in the MYD88 gene have been described in the majority of WM cases. The mutation is responsible for a gain-of-function and induces activation of nuclear factor-κB, for DNA transcription and cell survival. It seems that MYD88 mutation is associated with better prognosis and better response to some treatment. Treatments are started when WM is symptomatic, following systematic biological and morphological assessments. Therapeutic choice depends on age, frailty and urgent efficacy need. In first line, the majority of patients are treated with monoclonal anti-CD20 antibody-based regimens combined with cytotoxic chemotherapy. Rituximab, cyclophosphamide and dexamethasone remain the most commonly used regimen with good safety. Nevertheless, increasing numbers of new drugs are becoming available or are in development. Proteasome inhibitors, such as bortezomib or carfilzmib, showed good and rapid responses. Bruton tyrosine kinase (BTK) inhibitor demonstrated excellent results and is now available for relapse/refractory disease or as first line for some patients. This review highlights the diagnostic procedures and therapeutic approaches in WM.

The importance of the genomic landscape in Waldenström's Macroglobulinemia for targeted therapeutical interventions

The Literature has recently reported on the importance of genomics in the field of hematologic malignancies, including B-cell lymphoproliferative disorders such as Waldenström's Macrolgobulinemia (WM). Particularly, whole exome sequencing has led to the identification of the MYD88L265P and CXCR4C1013G somatic variants in WM, occurring in about 90% and 30% of the patients, respectively. Subsequently, functional studies have demonstrated their functional role in supporting WM pathogenesis and disease progression, both in vitro and in vivo, thus providing the pre-clinical evidences for extremely attractive targets for novel therapeutic interventions in WM. Of note, recent evidences have also approached and defined the transcriptome profiling of WM cells, revealing a signature that mirrors the somatic aberrations demonstrated within the tumor clone. A parallel research field has also reported on microRNAs (miRNAs), highlighting the oncogenic role of miRNA-155 in WM. In the present review, we focus on the latest reports on genomics and miRNAs in WM, providing an overview of the clinical relevance of the latest acquired knowledge about genomics and miRNA aberrations in WM.

A rare neurological complication of Waldenstrom's Macroglobulinemia

Bilateral and simultaneous facial nerve palsy (FNP) is a rare clinical condition occurring in 0.3-2.0% of facial palsy cases and is typically a manifestation of an underlying systemic disease. We here describe a case of a 67-year-old Hispanic man with a known history of Waldenstrom's Macroglobulinemia (WM) who presented to the clinic with a sub-acute onset of bilateral facial weakness. No alternate etiology for the facial weakness was identified after a thorough diagnostic approach. WM is a rare hematological condition due to low-grade B cell lymphoma, where lymphoplasmacytoid cells infiltrate different tissues and secrete monoclonal IgM. Peripheral neuropathy develops in 15-30% of the cases, being usually a chronic, progressive, symmetric, predominantly distal polyneuropathy. Facial nerve impairment is unusual; however, it could be caused by anoxic damage as a result of an increased blood viscosity from IgM monoclonal gammopathy, direct nerve infiltration of tumorous cells and an antibody (anti-MAG) mediated demyelinating process. Treatment is directed to the established mechanism for neural injury. This report highlights a rare condition (WM) with a rare complication (bilateral facial nerve palsy) and illustrates the broad differential comprised by this presenting complaint.

Recurrent chylothorax: a clinical mystery

Chylothorax is an unusual cause of pleural effusion, typically caused by trauma or malignancy. Waldenstrom's macroglobulinaemia (WM) is a clinicopathological entity demonstrating lymphoplasmacytic lymphoma in the bone marrow with an IgM monoclonal gammopathy in the blood. Recurrent chylous effusions are often resistant to conservative treatment and may require surgical intervention. We present a unique case of a 50-year-old woman with recurrent chylothorax secondary to WM that completely resolved with ibrutinib therapy. To our knowledge, this is the eighth such case reported in literature and the first case of successful resolution of chylothorax with monoclonal antibody therapy.

Novel Molecular Mechanism of Regulation of CD40 Ligand by the Transcription Factor GLI2

The interaction between tumor cells and their surrounding microenvironment is essential for the growth and persistence of cancer cells. This interaction is mediated, in part, by cytokines. Although the role of cytokines in normal and malignant cell biology is well established, many of the molecular mechanisms regulating their expression remain elusive. In this article, we provide evidence of a novel pathway controlling the transcriptional activation of CD40L in bone marrow-derived stromal cells. Using a PCR-based screening of cytokines known to play a role in the biology of bone marrow malignancies, we identified CD40L as a novel GLI2 target gene in stromal cells. CD40L plays an important role in malignant B cell biology, and we found increased Erk phosphorylation and cell growth in malignant B cells cocultured with CD40L-expressing stromal cells. Further analysis indicated that GLI2 overexpression induced increased CD40L expression, and, conversely, GLI2 knockdown reduced CD40L expression. Using luciferase and chromatin immunoprecipitation assays, we demonstrate that GLI2 directly binds and regulates the activity of the CD40L promoter. We found that the CCR3-PI3K-AKT signaling modulates the GLI2-CD40L axis, and GLI2 is required for CCR3-PI3K-AKT-mediated regulation of the CD40L promoter. Finally, coculture of malignant B cells with cells stably expressing human CD40L results in increased Erk phosphorylation and increased malignant B cell growth, indicating that CD40L in the tumor microenvironment promotes malignant B cell activation. Therefore, our studies identify a novel molecular mechanism of regulation of CD40L by the transcription factor GLI2 in the tumor microenvironment downstream of CCR3 signaling.

Diagnosis and management of neuropathies associated with plasma cell dyscrasias

Neuropathies associated with plasma cell dyscrasias are a major cause of morbidity for patients managed by medical oncologists. Because of similarities in clinical presentation and on nerve conduction studies, identifying the underlying disease leading to a paraproteinemic neuropathy can often be difficult. In addition, the degree of neurologic deficit does not strictly correlate with the extent of abnormalities on common clinical laboratory testing. Fortunately, with increasing understanding into the biologic mechanisms of underlying hematologic diseases, additional biomarkers have recently been developed, thus improving our diagnostic capacity. Neuropathies associated with plasma cells dyscrasias are seen with Monoclonal gammopathy of undetermined significance (MGUS) particularly IgM subtype, followed by IgG and IgA MGUS, multiple myeloma, Waldenström's macroglobulinemia, amyloid, Castleman's disease, and POEMS syndrome. The mechanisms of neuronal injury associated with plasma cell dyscrasia vary based on underlying diagnosis and include malignant infiltration, immune-mediated antibody deposition, or local compression of nerve roots. The polyneuropathies are frequently demyelinating, although axonal and mixed neuropathies can also be seen. As demonstrated by the cases included in this review, patients frequently present with symmetric sensory disturbance, followed by progressive motor weakness. Unfortunately, because of the complexity of diagnostic testing, patients are frequently examined late, often after receiving several ineffective therapies. The aim of this case-based review is to provide clinicians with insight on how to properly recognize these atypical neuropathies and send the appropriate diagnostic work, increasing the likelihood of accurately classify the patient's underlying hematologic disorder.

Waldenström's macroglobulinemia masquerading as ovarian cancer with peritoneal carcinomatosis, ascites, and elevated CA-125

Waldenström's macroglobulinemia is a rare hematology malignancy which often presents with "B symptoms," anemia, and thrombocytopenia. A 46-year-old woman presented with 2 months of abdominal distension accompanied by an unintentional 20-lb weight loss. Her abdominal CT scan demonstrated diffuse carcinomatosis with bilateral ovarian lesions and screening labs revealed a markedly elevated CA-125, suggesting a diagnosis of ovarian cancer. Upon admission for workup, patient was found to have a significant protein gap, later attributed to a markedly elevated IgM. Omental and bone marrow biopsy confirmed the diagnosis of Waldenström's macroglobulinemia, with elevation in CA-125 thought to be secondary to peritoneal irritation. This patient has since been successfully treated with six cycles of bendamusine and rituximab with no evidence of disease on staging scans and normalization of both CA-125 and IgM. To our knowledge, this is the first documented case of Waldenström's macroglobulinemia presenting with symptoms classically associated with ovarian cancer and demonstrates the importance of maintaining a broad differential when evaluating patients with abdominal carcinomatosis.

Preclinical models of Waldenström's macroglobulinemia and drug resistance

Newer therapeutic strategies are emerging in Waldenström's Macroglobulinemia (WM), which has traditionally been an orphan disease diagnosis. Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor was FDA-approved in 2015 as the first ever drug for the treatment of WM. This being a targeted therapy, has given rise to increased research into novel agents and pathways that can be exploited for clinical benefit in WM. In order to understand the underlying mechanisms of disease behavior as well as to test the benefit of various drugs, appropriate preclinical models are required. Historically there had been a lack of representative preclinical models in WM, but in recent years this has dramatically changed. This review highlights the currently available preclinical models and data regarding drug resistance pathways in WM. Knowledge from these will certainly help in paving the future course of treatment in this rare disorder which is indolent and yet, so far incurable.

Simultaneous occurrence of fibrillary glomerulonephritis and renal lesions in nonmalignant monoclonal IgM gammopathy

BACKGROUND

Fibrillary glomerulonephritis (FGN) is a rare primary glomerular disease that seldom coexists with other diseases. Membranoproliferative glomerulonephritis is a pathologic finding of renal lesions associated with IgM-secreting monoclonal proliferations. We present a case study of a patient with unusual simultaneous FGN and IgM-related renal disorder in nonmalignant monoclonal IgM gammopathy.

CASE PRESENTATION

A 63-year-old male presented with nephrotic syndrome and elevated serum creatinine levels. Laboratory examination revealed elevated levels of serum IgM and low C3 levels. Serum and urine immunofixation electrophoresis showed a monoclonal IgM with a kappa light chain. A bone marrow biopsy revealed less than 5 % bone marrow infiltration by lymphoplasmacytic lymphoma, and a renal biopsy revealed mesangiocapillary glomerulonephritis on light microscopy. Immunofluorescent and immunohistochemical staining indicated granular deposits of immunoglobulin G in the mesangium and granular deposits of immunoglobulin M and κ light chains along the capillary wall. Electron microscopy revealed randomly arranged nonbranching fibrils of approximately 15 nm in diameter in the glomerular mesangium and subendothelial electron-dense deposits. According to these results, we confirmed FGN and membranoproliferative glomerulonephritis, which were attributed to monoclonal IgM deposits.

CONCLUSION

To the best of our knowledge, this is the first report of simultaneous FGN and membranoproliferative glomerulonephritis in nonmalignant IgM monoclonal gammopathy.

Modulation of the IL-6 Receptor α Underlies GLI2-Mediated Regulation of Ig Secretion in Waldenström Macroglobulinemia Cells

Ig secretion by terminally differentiated B cells is an important component of the immune response to foreign pathogens. Its overproduction is a defining characteristic of several B cell malignancies, including Waldenström macroglobulinemia (WM), where elevated IgM is associated with significant morbidity and poor prognosis. Therefore, the identification and characterization of the mechanisms controlling Ig secretion are of great importance for the development of future therapeutic approaches for this disease. In this study, we define a novel pathway involving the oncogenic transcription factor GLI2 modulating IgM secretion by WM malignant cells. Pharmacological and genetic inhibition of GLI2 in WM malignant cells resulted in a reduction in IgM secretion. Screening for a mechanism identified the IL-6Rα (gp80) subunit as a downstream target of GLI2 mediating the regulation of IgM secretion. Using a combination of expression, luciferase, and chromatin immunoprecipitation assays we demonstrate that GLI2 binds to the IL-6Rα promoter and regulates its activity as well as the expression of this receptor. Additionally, we were able to rescue the reduction in IgM secretion in the GLI2 knockdown group by overexpressing IL-6Rα, thus defining the functional significance of this receptor in GLI2-mediated regulation of IgM secretion. Interestingly, this occurred independent of Hedgehog signaling, a known regulator of GLI2, as manipulation of Hedgehog had no effect on IgM secretion. Given the poor prognosis associated with elevated IgM in WM patients, components of this new signaling axis could be important therapeutic targets.

Lymphoplasmacytic lymphoma and marginal zone lymphoma in the bone marrow: paratrabecular involvement as an important distinguishing feature

OBJECTIVES

The differential diagnosis between bone marrow involvement by lymphoplasmacytic lymphoma (LPL) and marginal zone lymphoma (MZL) is challenging because histology and immunophenotype of both diseases overlap. We revisited the diagnostic pathology features of both diseases in the bone marrow.

METHODS

We studied a series of bone marrow trephine biopsy specimens from 59 patients with Waldenström macroglobulinemia without extramedullary involvement and bone marrow biopsy specimens from 23 patients with well-characterized MZL who also had bone marrow involvement. H&E- and immunoperoxidase-stained sections of bone marrow trephine biopsy specimens as well as flow cytometry and classic cytogenetics performed on aspirations were reviewed. The study was complemented with MYD88 L265P mutation analysis of all samples.

RESULTS

The most distinguishing features of LPL with respect to MZL were focal paratrabecular involvement (P < .001), the presence of lymphoplasmacytoid cells (P < .001) and Dutcher bodies (P < .001), increased numbers of mast cells (P < .001), and the MYD88 L265P mutation (P < .001).

CONCLUSIONS

LPL can be reliably distinguished from MZL in the bone marrow by using a combination of pathology characteristics. Our findings stress the diagnostic importance of using the combination of the following parameters for a correct LPL diagnosis: paratrabecular infiltration, the presence of lymphoplasmacytoid cells and cells with Dutcher bodies, and an increased number of mast cells in addition to the presence of MYD88 mutation.

Pathology of indolent B-cell neoplasms other than follicular lymphoma

Indolent B-cell lymphomas include follicular lymphoma (FL), chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and marginal zone lymphomas (MZLs). They are a diverse group of disorders with different clinical, morphological, immunophenotypic and genetic features. However, because of several histological similarities, such as in cell size and nodular structure, it may sometimes be difficult to differentiate them and to make a definitive diagnosis. In this review article, we summarize the histopathology of indolent B-cell neoplasms excluding FL and including hairy cell leukemia, and briefly mention recent genetic findings useful for their differential diagnosis. In addition, a provisional subtype of low-grade B-cell lymphoma, "prolymphocytic/paraimmunoblastic lymphoma", is described.

Cutaneous crystal storing histiocytosis: a report of two cases

Crystal storing histiocytosis (CSH) is a rare condition where crystals accumulate in the cytoplasm of macrophages and is usually associated with a lymphoplasmacytic neoplasm producing a monoclonal immunoglobulin with kappa light chain. CSH with primary manifestation in the skin is extraordinarily rare and limited to four case reports in the literature. Here we present two cases of cutaneous CSH. One case is that of an 80 year old woman who presented with bilateral periorbital oedema with yellow discolouration. Skin biopsy showed dermal CSH in association with a neoplastic lymphoplasmacytoid infiltrate showing IgM kappa light chain restriction. Subsequent work up led to the discovery of Waldenstrom's macroglobulinemia. She had an indolent clinical course but died 6 years later from transformation into a diffuse large B cell lymphoma in the bone marrow. The other case is that of a 52 year old man who was recently diagnosed with multiple myeloma and developed a pruritic rash on his back during chemotherapy. Skin biopsy showed Grover disease (transient acantholytic dermatosis) and crystal storing macrophages in the superficial dermis. He died 4 years later after a protracted clinical course involving multiple cycles of chemotherapy and numerous complications. In both patients cutaneous CSH occurred early in the course of their lymphoplasmacytic malignancy and its development did not herald rapid clinical decline.

Waldenström's macroglobulinemia - a review

Waldenström's macroglobulinemia (WM) is a lymphoproliferative disease of B lymphocytes, characterized by a lymphoplasmocytic lymphoma in the bone marrow and by IgM monoclonal hypergammaglobulinemia. It was first described in 1944 by Jan Gösta Waldenström, reporting two patients with oronasal bleeding, lymphadenopathy, anemia, thrombocytopenia, high erythrocyte sedimentation rate and serum viscosity, normal radiography and bone marrow infiltrated by lymphoid cells. The WM is a rare disease with a typically indolent clinical course, affecting mainly individuals aged between 63 and 68 years. Most patients have clinical signs and symptoms related to hyperviscosity resulting from IgM monoclonal gammopathy, and/or cytopenias resulting from bone marrow infiltration by lymphoma. The differential diagnosis with other lymphomas is essential for the assessment of prognosis and therapeutic approach. Treatment of patients with asymptomatic WM does not improve the quality of life of patients, or increase their survival, being recommended, therefore, their follow-up. For the treatment of symptomatic patients, alkylating agents, purine analogs and anti-CD20 monoclonal antibodies are used. However, the disease is incurable and the response to therapy is not always favorable. Recent studies have shown promising results with bortezomib, an inhibitor of proteasomes, and some patients respond to thalidomide. In patients with relapse or refractory to therapy, autologous transplantation may be indicated. The aim of this paper is to describe in detail the current knowledge on the pathophysiology of WM, main clinical manifestations, diagnosis, prognosis and treatment.

It is time to move forward with Waldenström!

In this issue of Blood, Roccaro et al demonstrate high expression of C-X-C chemokine receptor type 4 (CXCR4) mutation in Waldenström macroglobulinemia (WM), a marker of tumor aggression and drug resistance. In vivo analysis with an anti-CXCR4 antibody reversed this aggression, setting the stage for prospective studies in this forgotten disease.

[Bing-Neel syndrome: Report of 4 cases and literature review]

INTRODUCTION

Neurological manifestations during Waldenstrom disease are common and are usually related to immune peripheral neuropathy or serum hyperviscosity syndrome. The infiltration of the central nervous system by the lymphoproliferative syndrome is known as the Bing-Neel syndrome. This extremely rare entity remains poorly described in the literature.

CASE REPORTS

We report on 4 cases of patients for whom central neurological disorders led to the diagnosis of a Bing and Neel syndrome. These four cases illustrate different clinical presentations, diagnosis, therapeutic options, and outcome in this syndrome. Based on our literature review, we discuss about these differences.

CONCLUSION

The polymorphic clinical manifestations of Bing and Neel syndrome can mimic many diagnoses. However, it may be necessary to consider this diagnosis. Cerebrospinal fluid analysis and MRI may allow rapid diagnosis or guide a biopsy. Prolonged remissions are possible with appropriate treatment.

Waldenstrom's Macroglobulinemia and Peripheral Neuropathy, Organomegaly, Endocrinopathy, Monoclonal Gammopathy, and Skin Changes with a Bleeding Diathesis and Rash

We report a case of a 29-year-old male who presented with paraesthesia and skin lesions with excessive bleeding after skin biopsy leading to hematology consultation. He was found to have prolonged partial thromboplastin time (PTT) and monoclonal gammopathy on serum protein electrophoresis (SPEP). He experienced excessive bleeding leading to hospitalization after bone marrow biopsy and required blood transfusion. He was diagnosed with Waldenstrom's Macroglobulinemia (WM), based on the presence of IgM-κ type monoclonal (M) protein and infiltration of lymphoplasmacytic cells identified in bone marrow aspirates. He was noticed to have features of peripheral neuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS syndrome). This is a very rare case of WM with POEMS syndrome which responded to chemotherapy using bortezomib, steroids, and rituximab.

Waldenström macroglobulinemia: clinical and immunological aspects, natural history, cell of origin, and emerging mouse models

Waldenström macroglobulinemia (WM) is a rare and currently incurable neoplasm of IgM-expressing B-lymphocytes that is characterized by the occurrence of a monoclonal IgM (mIgM) paraprotein in blood serum and the infiltration of the hematopoietic bone marrow with malignant lymphoplasmacytic cells. The symptoms of patients with WM can be attributed to the extent and tissue sites of tumor cell infiltration and the magnitude and immunological specificity of the paraprotein. WM presents fascinating clues on neoplastic B-cell development, including the recent discovery of a specific gain-of-function mutation in the MYD88 adapter protein. This not only provides an intriguing link to new findings that natural effector IgM⁺IgD⁺ memory B-cells are dependent on MYD88 signaling, but also supports the hypothesis that WM derives from primitive, innate-like B-cells, such as marginal zone and B1 B-cells. Following a brief review of the clinical aspects and natural history of WM, this review discusses the thorny issue of WM's cell of origin in greater depth. Also included are emerging, genetically engineered mouse models of human WM that may enhance our understanding of the biologic and genetic underpinnings of the disease and facilitate the design and testing of new approaches to treat and prevent WM more effectively.

Candidate genes of Waldenström's macroglobulinemia: current evidence and research

Waldenström's macroglobulinemia (WM) is a relatively uncommon, indolent malignancy of immunoglobulin M-producing B cells. The World Health Organization classifies it as a lymphoplasmacytic lymphoma and patients typically present with anemia, hepatosplenomegaly and diffuse lymphadenopathies. Historically, the genetic characterization of the disease has been hampered by the relatively low proliferative rate of WM cells, thus making karyotyping challenging. The use of novel technologies such as fluorescence in situ hybridization, gene array, and whole genome sequencing has contributed greatly to establishing candidate genes in the pathophysiology of WM and to identifying potential treatment targets, such as L265P MYD88. The discovery of microRNAs and the recognition of epigenetics as a major modulatory mechanism of oncogene expression and/or oncosuppressor silencing have aided in further understanding the pathogenesis of WM. Once thought to closely resemble multiple myeloma, a cancer of terminally differentiated, immunoglobulin-secreting plasma cells, WM appears to genetically cluster with other indolent B-cell lymphomas such as chronic lymphocytic leukemia/small cell lymphoma. The relative high incidence of familial cases of WM and other B-cell malignancies has been helpful in identifying high-risk gene candidates. In this review, we focus on the established genes involved in the pathogenesis of WM, with special emphasis on the key role of derangement of the nuclear factor kappa B signaling pathway and epigenetic mechanisms.

Genomic analysis of marginal zone and lymphoplasmacytic lymphomas identified common and disease-specific abnormalities

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% 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) was found in nodal, splenic marginal zone and lymphoplasmacytic lymphomas and loss of 7q32.1-q33 was found in MALT, splenic and lymphoplasmacytic lymphomas. Abnormalities affecting the nuclear factor kappa B 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.

Waldenström macroglobulinemia: a review of the entity and its differential diagnosis

The definition of Waldenström macroglobulinemia (WM), originally described in 1944, has been refined substantially over time. The current fourth edition of the World Health Organization of lymphoid neoplasms, in large part, adopted criteria proposed for WM at a consensus conference in 2002. WM is defined as lymphoplasmacytic lymphoma involving the bone marrow associated with a serum immunoglobulin (Ig) M paraprotein of any concentration. Morphologically, WM is composed of a variable mixture of lymphocytes, plasmacytoid lymphocytes, and plasma cells. Immunophenotypically, the neoplastic cells express monotypic IgM and light chain: B lymphocytes express pan-B-cell antigens and surface Ig are usually negative for CD5 and CD10; and plasma cells are typically positive for CD138, CD38, CD45, cytoplasmic Ig, and CD19 (in a substantial subset of cases). The putative cell of origin of WM is a postantigen selected memory B-cell that has undergone somatic hypermutation. The most common cytogenetic abnormality in WM is del(6q), usually in the region 6q23-24.3, present in 40% to 50% of cases. IGH gene translocations are rare and recurrent chromosomal translocations or gene aberrations have not been identified in WM. Here, we provide a historical perspective of WM, review clinical and pathologic aspects of the disease as it is currently defined, and discuss some practical issues in the differential diagnosis of WM that pathologists encounter in the signout of cases.