Waldenström macroglobulinemia: 2012 update on diagnosis, risk stratification, and management

Waldenström Macroglobulinemia: A Clinicopathological Profile and Review of Six Cases

Waldenström macroglobulinemia (WM) is an indolent B-cell neoplasm in which lymphoplasmacytic cells are accumulated in the bone marrow. This rare disease is incurable with the available treatments and its management is generally based on risk-adapted methods. We present here six cases of WM with their clinicopathological profile and response to therapy. This is a retrospective observational study conducted in a tertiary referral center in Eastern India from October 2014 to December 2016. The clinical manifestations, diagnostic challenges, and response to therapy for WM were analyzed. A total of six cases of WM were analyzed, of which five were male; the mean age was 65 years. The most common presentation was transfusion-dependent anemia, followed by hyperviscosity. All the patients had bone marrow infiltration by lymphoplasmacytoid cells, and serum protein electrophoresis and immunofixation showed immunoglobulin M kappa monoclonal protein. Bortezomib, dexamethasone, and rituximab (BDR) was the most commonly used regimen. Complete and very good partial responses were seen in one patient (16.7%) each and partial response in 3 (50%) patients. There was disease progression to diffuse large B-cell lymphoma in one patient (16.7%). After a 26-month follow-up, four of six patients (66.67%) remained free of disease progression. A very low incidence of WM was reported, and patients had a varied clinicopathological spectrum. A combination of BDR is a promising frontline therapy in the patients of WM.

Management of intraoral bleeding in patients with Waldenström macroglobulinemia: A protocol proposal

AIM

Waldenström macroglobulinemia is a type of non-Hodgkin lymphoma with poor prognosis observed in patients with hyperviscosity syndrome because of its tendency for fatal symptoms. This study investigated the risk of intraoral bleeding in patients with Waldenström macroglobulinemia based on hyperviscosity syndrome stage and oral health status, and described potential strategies for managing intraoral bleeding.

METHODS AND RESULTS

Between April 2012 and March 2017, seven patients with Waldenström macroglobulinemia underwent dental procedures or tooth extraction. Patient records were retrospectively reviewed to obtain data of symptoms, clinical and radiographic findings, treatment details, pretreatment hematological findings, hyperviscosity syndrome status, perioperative method for local haemostasis, postoperative bleeding, and prognosis. The mean patient age was 71.2 years, and the male-to-female ratio was 6:1. Treatment modalities for oral management comprised tooth extraction, scaling, and oral cavity cleaning. Three patients were admitted for hyperviscosity syndrome; one of the patients exhibited postoperative bleeding because of poor oral hygiene, whereas the two other patients with good oral hygiene did not experience intraoral bleeding regardless of the presence of hyperviscosity syndrome.

CONCLUSION

We recommended that the risk of oral bleeding in patients with Waldenstrom's macroglobulinemia should be assessed for oral health in addition to the stage of hyperviscosity syndrome.

Wild-type Blocking PCR Combined with Direct Sequencing as a Highly Sensitive Method for Detection of Low-Frequency Somatic Mutations

Accurate detection and identification of low frequency mutations can be problematic when assessing residual disease after therapy, screening for emerging resistance mutations during therapy, or when patients have few circulating tumor cells. Wild-type blocking PCR followed by sequencing analysis offers high sensitivity, flexibility, and simplicity as a methodology for detecting these low frequency mutations. By adding a custom designed locked nucleic acid oligonucleotide to a new or previously established conventional PCR based sequencing assay, sensitivities of approximately 1 mutant allele in a background of 1,000 WT alleles can be achieved (1:1,000). Sequencing artifacts associated with deamination events commonly found in formalin fixed paraffin embedded tissues can be partially remedied by the use of uracil DNA glycosylase during extraction steps. The optimized protocol here is specific for detecting MYD88 mutation, but can serve as a template to design any WTB-PCR assay. Advantages of the WTB-PCR assay over other commonly utilized assays for the detection of low frequency mutations including allele specific PCR and real-time quantitative PCR include fewer occurrences of false positives, greater flexibility and ease of implementation, and the ability to detect both known and unknown mutations.

Once-weekly ofatumumab in untreated or relapsed Waldenström's macroglobulinaemia: an open-label, single-arm, phase 2 study

BACKGROUND

The development of more effective and safer treatments, especially non-chemotherapeutics, is needed for patients with Waldenström's macroglobulinaemia. The aim of the study was to assess the safety and clinical activity of intravenous ofatumumab monotherapy for untreated and relapsed Waldenström's macroglobulinaemia.

METHODS

We did a phase 2, open-label, single-arm study at six centres (hospitals and cancer clinics) in the USA. Patients aged at least 18 years who were diagnosed with untreated or relapsed Waldenström's macroglobulinaemia and required treatment, received up to three cycles of weekly ofatumumab for 5 weeks. For cycle 1, patients received one of two treatment regimens. Group A received ofatumumab 300 mg during week 1 followed by 1000 mg during weeks 2-4. Because of the acceptable safety of the 1000 mg dose in treatment group A and clinical activity of the 2000 mg dose established in chronic lymphocytic leukaemia, the study was amended on Dec 9, 2009, to change cycle 1 for group B who received ofatumumab 300 mg during week 1 and 2000 mg during weeks 2-5. We followed up patients during weeks 5-16 for treatment group A and during weeks 6-16 for treatment group B (no treatment was given during this follow-up). Patients in both groups with stable disease or a minor response after 16 weeks were eligible to then receive a redosing cycle of ofatumumab 300 mg during week 1 and 2000 mg during weeks 2-5. We followed up patients during weeks 6-16 after the redosing cycle (no treatment was given during this follow-up). Patients responding to cycle 1 or the redosing cycle who developed disease progression within 36 months could receive cycle 2 of ofatumumab 300 mg during week 1 and 2000 mg during weeks 2-5. The primary endpoint for this study was the proportion of patients who achieved an overall response (complete responses plus partial responses plus minor responses) after each treatment cycle in the intent-to-treat population every 4 weeks starting at week 8. This trial is registered at www.ClinicalTrials.gov, NCT00811733, and is now complete.

FINDINGS

Between March 17, 2009, and Feb 24, 2011, we enrolled and assigned 37 patients to treatment (15 in treatment group A and 22 in treatment group B). All 37 were included in the efficacy and safety analyses. 19 (51%, 95% CI 34·4-68·1) of 37 patients achieved an overall response after cycle 1 and 22 (59%, 42·1-75·2) of 37 achieved an overall response after the redosing cycle; 15 (41%) with partial responses, seven (19%) with minor responses. 13 patients received treatment cycle 2; ten (77%) of the 13 achieved a response. All 37 patients had at least one adverse event; 16 (43%) patients had events of grade 3 or more (30 grade 3, one grade 4). The most common grade 3 or 4 adverse events were infusion reactions (four [11%] of 37), chest pain (two [5%] of 37), haemolysis (two [5%] of 37), and neutropenia (two [5%] of 37). Two (9%) of 22 patients (both in treatment group B) had an IgM flare. 12 patients reported serious adverse events; haemolysis and pyrexia were the most common (each occurring in two [5%] of 37 patients).

INTERPRETATION

A high proportion of patients achieved an overall response with ofatumumab monotherapy and this treatment was well tolerated, with a low incidence of IgM flare. This therapy might be a non-chemotherapeutic treatment option for patients with Waldenström's macroglobulinaemia, especially those with high IgM concentrations.

FUNDING

GlaxoSmithKline and Genmab.

PRIMA-1Met induces apoptosis in Waldenström's Macroglobulinemia cells independent of p53

PRIMA-1Met has shown promising preclinical activity in various cancer types. However, its effect on Waldenström's Macroglobulinemia (WM) cells as well as its exact mechanism of action is still elusive. In this study, we evaluated the anti- tumor activity of PRIMA-1Met alone and in combination with dexamethasone or bortezomib in WM cell lines and primary samples. Treatment of WM cells with PRIMA-1Met resulted in induction of apoptosis, inhibition of migration and suppression of colony formation. Upon PRIMA-1Met treatment, p73 was upregulated and Bcl-xL was down-regulated while no significant change in expression of p53 was observed. Furthermore, siRNA knockdown of p53 in WM cell line did not influence the PRIMA-1Met-induced apoptotic response whereas silencing of p73 inhibited latter response in WM cells. Importantly, combined treatment of BCWM-1 cells with PRIMA-1Met and dexamethasone or bortezomib induced synergistic reduction in cell survival. Our study provides insights into the mechanisms of anti-WM activity of PRIMA-1Met and supports further clinical evaluation of PRIMA-1Met as a potential novel therapeutic intervention in WM.

Positive selection and high sensitivity test for MYD88 mutations using locked nucleic acid

INTRODUCTION

Detection of mutations in the myeloid differentiation primary response gene 88 (MYD88) has clinical implications on diagnosis and therapy, especially in patients with Waldenström's macroglobulinemia (WM) and IgM monoclonal gammopathy of unknown significance (IgM-MGUS). We describe a method that provides greatly increased sensitivity for detecting minority mutations in MYD88.

METHODS

We used a locked nucleic acid oligonucleotide to block amplification of wild-type DNA during polymerase chain reaction (PCR). Sanger sequencing of amplified DNA was used for detecting mutations in MYD88 gene. This approach was used to test samples from patients with WM and IgM-MGUS.

RESULTS

When compared to traditional PCR followed by Sanger sequencing, our methodology was significantly more sensitive (one mutant allele in a background of 200 wild-type alleles). Using sequencing allowed us to visualize the PCR product, giving advantages over other methodologies such as allele-specific PCR. Based on analyzing 36 randomly selected, MYD88 mutated, clinically tested samples, we demonstrate that traditional PCR failed to detect MYD88 mutations in 64% of the samples that were clearly positive by wild-type blocking PCR.

CONCLUSION

The new methodology is essential for attaining accurate results in clinical testing.

Determination of whole blood and plasma viscosity in term neonates by flow curve analysis with the LS300 viscometer1

Determination of shear stresses at given shear rates allow approximation of flow curves by mathematical models and to calculate viscosities of non-Newtonian fluids. In term neonates, the mean arterial blood pressure (MAP) is markedly below that of adults, therefore rheological properties of blood play an important role in maintaining perfusion. Whole blood viscosity was measured in umbilical cord blood taken from 62 term neonates using the LS 300 viscometer. Individual parameters that influence the viscosity of whole blood were measured: red blood cell (RBC) aggregation, plasma viscosity, hematocrit, and RBC deformability. The flow curve of whole blood of neonates was approximated by the method of Ostwald with the highest quality whereas in adults the best approximation was found by the method of Casson. With hematocrits of 0.40, the viscosity of whole blood in newborns approximated by Ostwald (9.84 ± 5.12 mPa·s) was significantly lower than that of adults (15.34 ± 3.01 mPa·s). The aggregation index of the blood of newborns was markedly lower (2.98 ± 2.12) than in adults (14.63 ± 3.50) whereas RBC deformability was higher in neonates. The viscosity of plasma determined by Ostwald revealed a lower exponent (n) in neonates (0.94 ± 022) compared to adults (1.01 ± 0.12) and the viscosity determined by Newton was lower in neonates (1.04 ± 0.16 mPa·s) than in adults (1.19 ± 0.07 mPa·s). The flow curve of neonatal blood which is best approximated by the model of Ostwald emphasizes its important viscous properties necessary for conditions with physiologically low blood pressure.

Superior efficacy of rituximab-based chemoimmunotherapy as an initial therapy in newly diagnosed patients with B cell indolent lymphomas: long-term results from a single center in China

Background

Rituximab has been confirmed to improve the survival of patients with B cell indolent non-Hodgkin lymphomas (B-iNHLs) in Western world as previously reported, however, it is rarely reported in Chinese cohort. This study is to investigate the efficacy and safety of rituximab-based chemoimmunotherapy and select subpopulations most sensitive to the regimen in Chinese B-iNHL patients.

Methods

334 B-iNHL patients from our center were retrospectively assessed.

Results

Patients received R-based chemoimmunotherapy showed significantly higher rates of overall response (OR) (93.0 % vs. 53.4 %, P < 0.001) and complete response (CR) (63.3 % vs. 16.0 %, P < 0.001) compared with the patients received other therapies. Survival analysis showed that rituximab-based chemoimmunotherapy could obviously improve the progression-free survival (PFS) (110 vs. 49 months, P = 0.001) and overall survival (OS) (120 vs. 72 months, P < 0.001) in patients with B-iNHLs. Interestingly, in chronic lymphocytic leukemia (CLL) patients, we found that the patients with β2-microglobulin (β2-MG) < 3.5 mg/L, lactate dehydrogenase (LDH) < 220 U/L, zeta-chain-associated protein kinase 70 (ZAP-70) negative, and non high-risk genetic abnormality could achieve more benefits from R-based regimens with higher CR rate (P = 0.003, 0.029, 0.013 and 0.038, respectively). Meanwhile, more CLL patients achieved minimal residual disease (MRD) negative after rituximab-based treatment (46.5 % vs. 10.3 %, P < 0.001). Moreover, CLL patients with MRD < 1 %, LDH < 220 U/L, complete remission (CR) or partial remission (PR), β2-MG < 3.5 mg/L and non high-risk cytogenetic abnormality showed superior outcome compared to the controls (P = 0.001, 0.000, 0.000, 0.001 and 0.013, respectively). No other side-effects increased in chemoimmunotherapy group except the elevation of grade 3–4 neutropenia.

Conclusions

Our results demonstrate the superior efficacy of rituximab–based chemoimmunotherapy as an initial therapy in Chinese cohort with newly diagnosed B-iNHLs and further identify subpopulations that are more sensitive to R-based chemoimmunotherapy in CLL group.

Cutaneous deposits

: The cutaneous deposition disorders are a group of unrelated conditions characterized by the accumulation of either endogenous or exogenous substances within the skin. These cutaneous deposits are substances that are not normal constituents of the skin and are laid down usually in the dermis, but also in the subcutis, in a variety of different circumstances. There are 5 broad categories of cutaneous deposits. The first group includes calcium salts, bone, and cartilage. The second category includes the hyaline deposits that may be seen in the dermis in several metabolic disorders, such as amyloidosis, gout, porphyria, and lipoid proteinosis. The third category includes various pigments, heavy metals, and complex drug pigments. The fourth category, cutaneous implants, includes substances that are inserted into the skin for cosmetic purposes. The fifth category includes miscellaneous substances, such as oxalate crystals and fiberglass. In this article, the authors review the clinicopathologic characteristics of cutaneous deposition diseases, classify the different types of cutaneous deposits, and identify all the histopathologic features that may assist in diagnosing the origin of a cutaneous deposit.

MYD88 mutant lymphoplasmacytic lymphoma/Waldenström macroglobulinemia has distinct clinical and pathological features as compared to its mutation negative counterpart

In a first series from India, we report 32 cases of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM) over 7 years. Here, we analyzed 32 patients with LPL/WM for MYD88 L265P mutation and correlated mutation staus with hematological and biochemical parameters and also with the International Prognostic Scoring System (ISSWM) and treatment response. Twenty-seven out of 32 cases of LPL/WM (84.3%) harbored the MYD88 L265P mutation. MYD88 wild-type WM was associated with a lower number of tumor cells (p<0.01) and older age (p=0.02) and a lower ISSWM score at presentation (p=0.03) as compared to mutated LPL/WM. On evaluation of response (n=23), 44.4% of patients with MYD88 mutated LPL/WM had progressive disease, whereas no patient in the MYD88 unmutated group changed their baseline status. We confirm the high frequency of MYD88 mutations in LPL/WM. Although the number of MYD88 wild-type cases was limited, our data indicate that MYD88 may represent an adverse prognostic marker for LPL/WM.

Genetic factors and pathogenesis of Waldenström's macroglobulinemia

Waldenström's macroglobulinemia (WM) is an indolent but incurable B-cell malignancy. Over the last decade, advances in the molecular field brought about by the use of high-throughput genomic analyses-including array-based comparative genomic hybridization and massively parallel genome sequencing-have considerably improved our understanding of the genetic basis of WM. Its pathogenesis, however, remains fragmented. Important steps have been made in elucidating the underlying aberrations and deregulated mechanisms of the disease, and thereby providing invaluable information for identifying biomarkers for disease diagnosis, risk stratification, and therapeutic approaches. We review the genetic basis of the disease.

Long-term outcome of monoclonal (type 1) cryoglobulinemia

The aim of this study is to investigate long-term outcome of symptomatic type 1 cryoglobulinemia (CG) and its determinants. Retrospective cohort study was conducted in two French University Hospitals. Patients with type 1 CG were identified using laboratory databases. Inclusion criterion was the presence of persistent symptoms of CG. Among 227 screened patients, 36 were included. Skin or vasomotor symptoms were the most frequent features (75%). Nephropathy and neuropathy occurred in 30% and 47% of cases, respectively. The underlying B cell disease (BCD) was a nonmalignant monoclonal gammopathy (NMMG) in 13 (36%) and a hematologic malignancy (HM) in 23 (64%; Waldenstrom macroglobulinemia (WM) in 12, low-grade non-Hodgkin lymphoma (NHL) in 6, multiple myeloma (MM) in 4, and chronic lymphocytic leukemia in 1 patient. Severe manifestations affected half the patients and were more frequent with IgG (82 vs. 30% (P = 0.006)). At last follow-up, 64% of patients had suffered no hematologic manifestation. Potent chemotherapeutic regimens were mainly used in HM. For patients with NMMG, WM, or NHL, fludarabine or rituximab-based regimens appeared to yield better responses. Five-year survival rate was 82%. In multivariate analysis, mortality was significantly higher in older patients (HR: 1.17 per year [95% CI: 1.06-1.28], P = 0.001) and those with nephropathy (HR: 8.9 [95% CI: 1.9-43], P = 0.006). Kidney disease, infections, Richter's transformation, and second malignancies were important sources of morbi-mortality. Despite its limitations, this series provide novel information regarding type 1 CG. Further studies are needed to improve its management. To date, therapeutic strategy should be tailored according to patient's characteristics (age, comorbidities, underlying BCD), and therapeutic target.

Waldenström macroglobulinemia: from biology to treatment

Waldenström macroglobulinemia (WM) is distinct B-cell lymphoproliferative disorder primarily characterized by bone marrow infiltration of lymphoplasmacytic cells along with production of a serum monoclonal (IgM). In this review, we describe the biology of WM, the diagnostic evaluation for WM with a discussion of other conditions that are in the differential diagnosis and clinical manifestations of the disease as well as current treatment options. Within the novel agents discussed are everolimus, perifosine, enzastaurin, panobinostat, bortezomib and carfilzomib, pomalidomide and ibrutinib. Many of the novel agents have shown good responses and have a better toxicity profile compared to traditional chemotherapeutic agents, which makes them good candidates to be used as primary therapies for WM in the future.

[A rare cause of pulmonary opacities: Lung localization of Waldenström's macroglobulinemia]

INTRODUCTION

Pulmonary localized forms of Waldenström's macroglobulinemia are rare.

CASE REPORT

We report the observation of a 71-year-old woman with chronic cough and persisting alveolar opacities after several courses of antibiotics. Physical examination was unremarkable. Protein electrophoresis identified a monoclonal IgM in the serum. The lymphocyte immunophenotyping from the bronchoalveolar lavage was consistent with a B-cell lymphoma and Waldenström's macroglobulinemia was confirmed by the bone marrow biopsy. Chemotherapy with a combination of rituximab, fludarabine and cyclophosphamide improved the patient's symptoms and caused the pulmonary opacities to resolve. We discuss the various clinical and radiological pulmonary manifestations of this slowly progressive hematological condition.

CONCLUSION

Pulmonary manifestations of Waldenström's macroglobulinemia result in various clinical and radiological patterns. A serum protein electrophoresis should be performed in cases of pleuropulmonary opacities persisting despite antibiotics.

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.

Therapeutic effects of thalidomide in hematologic disorders: a review

The extensive autoimmune, anti-inflammatory, and anticancer applications of thalidomide have inspired a growing number of studies and clinical trials. As an inexpensive agent with relatively low toxicity, thalidomide is regarded as a promising therapeutic candidate, especially for malignant diseases. We review its therapeutic effects in hematology, including those on multiple myeloma, Waldenstroem macroglobulinemia, lymphoma, mantle-cell lymphoma, myelodysplastic syndrome, hereditary hemorrhagic telangiectasia, and graftversus-host disease. Most studies have shown satisfactory results, although several have reported the opposite. Aside from optimal outcomes, the toxicities and adverse effects of thalidomide should also be examined. The current work includes a discussion of the mechanisms through which the novel biological effects of thalidomide occur, although more studies should be devoted to this aspect. With appropriate safeguards, thalidomide may benefit patients suffering from a broad variety of disorders, particularly refractory and resistant diseases.

Standardization of sample collection, isolation and analysis methods in extracellular vesicle research

The emergence of publications on extracellular RNA (exRNA) and extracellular vesicles (EV) has highlighted the potential of these molecules and vehicles as biomarkers of disease and therapeutic targets. These findings have created a paradigm shift, most prominently in the field of oncology, prompting expanded interest in the field and dedication of funds for EV research. At the same time, understanding of EV subtypes, biogenesis, cargo and mechanisms of shuttling remains incomplete. The techniques that can be harnessed to address the many gaps in our current knowledge were the subject of a special workshop of the International Society for Extracellular Vesicles (ISEV) in New York City in October 2012. As part of the “ISEV Research Seminar: Analysis and Function of RNA in Extracellular Vesicles (evRNA)”, 6 round-table discussions were held to provide an evidence-based framework for isolation and analysis of EV, purification and analysis of associated RNA molecules, and molecular engineering of EV for therapeutic intervention. This article arises from the discussion of EV isolation and analysis at that meeting. The conclusions of the round table are supplemented with a review of published materials and our experience. Controversies and outstanding questions are identified that may inform future research and funding priorities. While we emphasize the need for standardization of specimen handling, appropriate normative controls, and isolation and analysis techniques to facilitate comparison of results, we also recognize that continual development and evaluation of techniques will be necessary as new knowledge is amassed. On many points, consensus has not yet been achieved and must be built through the reporting of well-controlled experiments.

Prevalence and clinical significance of the MYD88 (L265P) somatic mutation in Waldenström’s macroglobulinemia and related lymphoid neoplasms

Using a sensitive method, the MYD88 (L265P) mutation is detectable in all patients with Waldenström’s macroglobulinemia, therefore representing a hallmark of the disease. MYD88 (L265P) is also found in a substantial proportion of patients with IgM-MGUS.

Microarray demonstrates different gene expression profiling signatures between Waldenström macroglobulinemia and IgM monoclonal gammopathy of undetermined significance

Waldenström macroglobulinemia (WM) (symptomatic and indolent) and immunoglobulin M (IgM) monoclonal gammopathy of undetermined significance (IgMMGUS) can be identified based on the bone marrow (BM) infiltration and the existence of symptoms. The purpose of this study was to investigate the biological and genetic characteristics of both disorders comparing the molecular signature of WM versus IgMMGUS using microarray analysis. We investigated BM CD19(+) cells isolated from 21 WM patients and 10 IgMMGUS cases, and CD138(+) BM cells isolated from all of the WM patients and 4 of the IgMMGUS cases. Gene expression profiling of WM versus IgMMGUS CD19(+) cells highlighted 151 differently expressed genes and the comparison with CD138(+) cells demonstrated 43 differently expressed genes in WM versus IgMMGUS. Regulation of transcription, Janus kinase/signal transducer and activator of transcription, PI3K/Akt/mammalian target of rapamycin, mitogen-activated protein kinase signaling pathways are the relevant gene ontology biological processes occurring in CD19(+) cells, and immune response, cell activation, and signaling processes developing in CD138(+) cells mainly distinguish WM and IgMMGUS.

Genomic studies have identified multiple mechanisms of genetic changes in Waldenström macroglobulinemia

The pathophysiology of Waldenström macroglobulinemia (WM), a lymphoproliferative disorder characterized by lymphoplasmacytic bone marrow infiltration associated with serum IgM paraprotein, is rather unclear; however, progress has been made in recent years to better determine the genetic profile of WM tumor cells. Studies based on high-throughput genomic analyses-including single-nucleotide polymorphism array (SNPa), array-based comparative genomic hybridization, and, recently, whole-genome sequencing--have improved deciphering some of the key molecular pathways associated with WM. Beyond the discovery of the myeloid differentiation primary response gene 88 (MYD88) L265P mutation, which will help greatly in the differential characterization of WM from other B-cell low-grade lymphomas, several other mechanisms of gene deregulation were identified and mapped that recurrently pointed out nuclear factor-kappa B (NF-κB), breakpoint cluster region (BCR), and Toll-like receptor (TLR) signaling pathways as potential targets for a better understanding of the physiopathology of WM and for future drug development. Herein, we summarize the current knowledge of the genomic patterns of WM to highlight its complexity.

Diagnostic challenges of amyloidosis in Waldenström macroglobulinemia

Amyloidosis associated with immunoglobulin M clones is a distinct clinical entity that poses specific challenges to clinicians. Although there is substantial overlap, the pattern of organ involvement is peculiar, with higher frequencies of lung, lymph nodes, and peripheral nervous system involvement. Early diagnosis is vital to start effective therapy before irreversible organ damage has occurred and should be based on markers of initial, asymptomatic organ dysfunction, such as natriuretic peptides for heart involvement and albuminuria for renal amyloidosis. Immunoglobulin M clones can give rise to both light chain (AL) and reactive (AA) amyloidosis, and once the diagnosis of amyloidosis is made, correct amyloid typing is necessary to design appropriate therapy and follow-up. Prognostic stratification should include serum albumin concentration, which is an independent prognostic factor.

Reappraising the role of autologous transplantation for indolent B-cell lymphomas in the chemoimmunotherapy era: is it still relevant?

The role of autologous hematopoietic cell transplantation (auto-HCT) in the management of indolent non-Hodgkin lymphomas (NHL) is shrouded in controversy. The outcomes of conventional therapies for many indolent lymphoma subtypes have dramatically improved over the last several years with the use of monoclonal antibodies, maintenance therapy programs and with the incorporation of radio-immunoconjugates. These significant advances in the armamentarium of lymphoma therapeutics warrant reappraisal of the current role of auto-HCT in the treatment algorithm of indolent NHL. Prospective randomized studies comparing contemporary chemoimmunotherapies against auto-HCT are lacking, leading to significant debate about the role and timing of auto-HCT for indolent NHL in the modern era. Although autografting for follicular lymphoma (FL) in first remission has been largely abandoned, it remains a useful modality for relapsed disease, especially for the subgroup of patients who are not candidates for allogeneic transplantation with a curative intent. Auto-HCT can provide durable disease control in chemosensitive transformed FL and mantle cell lymphoma (MCL) in first remission, with relatively low toxicity, and remains appropriate in chemoimmunotherapy era. Contemporary data are also reviewed to clarify the often underutilized role of autografting in relapsed MCL and other less frequent indolent NHL histologies. The biological basis of the increased risks of second malignancies with auto-HCT are reviewed to identify strategies designed to mitigate this risk by, for example, avoiding exposure to genotoxic agents, planning early stem cell collection/cryopreservation and minimizing the use of TBI with transplant conditioning, and so on. Genetic testing able to identify patients at high risk of therapy-related complications and novel post-transplant immune therapies with the potential of transforming autografting in indolent NHL from a remission-extending therapy to a curative modality are discussed to examine the possibly expanding role of auto-HCT for lymphoid malignancies in the coming years.