Search

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. Summary: 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. [ABSTRACT FROM AUTHOR]

This study presents two cases of type II mixed cryoglobulinemia. One case is essential, while the other is presumably associated with hepatitis B virus (HBV) infection. Both patients tested positive for monoclonal IgMk, but negative for MyD88 mutation. They showed resistance to rituximab combined with a glucosteroid regimen, but responded positively to BTK inhibitors. These cases highlight the remarkable effectiveness of BTK inhibitors in treating refractory type II cryoglobulinemia without MyD88 mutation. The first patient achieved rapid complete remission of nephrotic syndrome within one month of starting ibrutinib, along with a significant reduction in cryoglobulin levels and abnormal clonal cells. The second patient had a rapid disappearance of rash within three days and accelerated wound healing within one week of initiating orelabrutinib, accompanied by a reduction in C-reactive protein. However, there was no reduction in cryoglobulin levels during the 12-month follow-up. These findings suggest varied mechanisms of action of BTK inhibitors in type II cryoglobulinemia through different mechanisms. [ABSTRACT FROM AUTHOR]

A rare subtype of diffuse large B-cell lymphoma (DLBCL) has been reported to be accompanied by elevated immunoglobulin M (IgM) paraprotein in the serum at diagnosis, called as IgMs-DLBCL. The monoclonal IgM paraprotein disappears soon after treatment in most of these patients. Here, we described a DLBCL patient with continuously elevated IgM following therapy. A 59-year-old male was diagnosed with DLBCL (GCB subtype per Hans algorithm, stage IA) with involvement of the right cervical lymph node. After six cycles of immunochemotherapy with the R-CHOP regimen, complete metabolic remission was achieved, but an elevated level of serum IgM persisted. To investigate the origin of elevated IgM, pathologic, immunophenotypic, and molecular analyses of lymph node and bone marrow (BM) samples were performed pre- and post-treatment. BM infiltration of lymphoplasmacytic cells, and a typical immunophenotypic profile by flow cytometry supported the diagnosis of Waldenström macroglobulinemia (WM). The MCD subtype of DLBCL was identified by next-generation sequencing of the lymph node at initial diagnosis characterized by cooccurring point mutations in MYD88L265P and CD79B. Additionally, two different dominant clonotypes of the immunoglobulin heavy chain (IGH) were detected in the lymph node and BM by IGH sequencing, which was IGHV 3--11*06/IGHJ 3*02 and IGHV 3--11*06/IGHJ 6*02, respectively, speculating to be two independent clonal origins. This study will provide a panoramic understanding of the origin or biological characteristics of DLBCL co-occurring with WM. [ABSTRACT FROM AUTHOR]

Purpose of Review: The discovery of recurring somatic mutations, in particular MYD88 and CXCR4 mutations, in Waldenström macroglobulinemia (WM), a rare B-cell lymphoproliferative disorder, led in the last decade to the development of several therapeutic agents with high efficacy. This review aims to provide an overview of available treatments in WM and novel agents, focusing on studies published over recent years. Recent Findings: There is no international consensus on the best first-line option in treatment-naïve patients. Randomized clinical trials are rare in WM and there has been no prospective comparison of chemoimmunotherapy and BTK inhibitors in the frontline setting. Summary: Chemoimmunotherapy and BTK inhibitors, the two feasible and most widely used treatments in first-line treatment, represent very different options in terms of duration of therapy, route of administration, cost, and adverse effect. In addition to tumor genotype and patient comorbidities, choice of therapy in WM should take into account these parameters. Results of ongoing and future clinical trials evaluating fixed-duration combinations with BTK inhibitors and novel agents are awaited. [ABSTRACT FROM AUTHOR]

Classification of DLBCL relies on clinical, immunohistochemical, and genetic information. We report a case of primary testicular diffuse large B-cell lymphoma (PT-DLBCL) with a hitherto unreported constellation of pathologic findings to illustrate the challenges of DLBCL classification. A standard hematopathology workup was followed by gene expression profiling (GEP) to determine the DLBCL cell of origin (COO). A 75-year-old man presented with a unilateral testicular mass that had developed over the course of 1 month. Pathologic examination demonstrated involvement by DLBCL. Clinical staging revealed no systemic disease. Genetic testing showed an MYD88 mutation, as well as IGH::MYC and IRF4- and BCL6-rearrangements. Gene expression profiling demonstrated an activated B-cell expression profile. This case highlights the genetic complexity of DLBCL arising in the testis and questions the clinical significance of the identified genetic abnormalities. [ABSTRACT FROM AUTHOR]

Waldenström's macroglobulinemia (WM) is a B-cell non-Hodgkin's lymphoma characterized by clonal IgM-secreting lymphoplasmacytic cell proliferation. Bing-Neel syndrome (BNS) is a rare complication of WM that results in the infiltration of the central nervous system (CNS) with IgM-secreting lymphoplasmacytic cells. This case study presents a 75-year-old Caucasian male with a history of WM and Agent Orange exposure who ultimately was diagnosed with BNS. This patient posed unique diagnostic challenges as the patient experienced clinical symptoms despite the absence of MRI abnormalities and therapeutic challenges., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Kotlarz et al.)

This study presents two cases of type II mixed cryoglobulinemia. One case is essential, while the other is presumably associated with hepatitis B virus (HBV) infection. Both patients tested positive for monoclonal IgMκ, but negative for MyD88 mutation. They showed resistance to rituximab combined with a glucosteroid regimen, but responded positively to BTK inhibitors. These cases highlight the remarkable effectiveness of BTK inhibitors in treating refractory type II cryoglobulinemia without MyD88 mutation. The first patient achieved rapid complete remission of nephrotic syndrome within one month of starting ibrutinib, along with a significant reduction in cryoglobulin levels and abnormal clonal cells. The second patient had a rapid disappearance of rash within three days and accelerated wound healing within one week of initiating orelabrutinib, accompanied by a reduction in C-reactive protein. However, there was no reduction in cryoglobulin levels during the 12-month follow-up. These findings suggest varied mechanisms of action of BTK inhibitors in type II cryoglobulinemia through different mechanisms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Xu, Xu, Yuan, Shang, Chen, Liu, Li, Liu, Liu, Wang, Ding, Xie and Hao.)

Diffuse large B cell lymphoma (DLBCL) is associated with aggressive clinical cases and poor prognosis despite recent advances in disease treatment. In activated B-cell-like (ABC)-DLBCL, the most severe damaged signaling pathways converge to aberrantly activate the Toll-like receptor (TLR) 7/9/MyD88 pathways, leading to the avoidance of cell death and resistance to chemotherapy. A gain of function mutation in MyD88 (MyD88 L265P) enhanced the NF-κB and JAK-STAT signaling pathways and was associated with dysregulation of TLR signaling in the pathogenesis of ABC-DLBCL. Therefore, inhibition of the TLR signaling network may improve clinical outcomes. In this study, we designed a de novo synthesized oligodeoxynucleotide-based antagonist of TLR7 and TLR9, referred to as HJ901, which competitively binds to TLR7/9. We profiled HJ901 inhibition in various DLBCL cell lines and verified tumor suppression in a xenograft mouse model. We found that HJ901 treatment significantly reduced TLR7- and TLR9-mediated cell proliferation and cytokine production in a time- and dose-dependent manner in various DLBCL cell lines expressing the MyD88 L265P mutation. Moreover, HJ901 prevented tumor growth and downregulated the NF-κB and JAK2-STAT3 signaling pathways in a DLBCL xenograft mouse model with the MyD88 L265P mutation. These results reveal that the anti-tumor effects of the synthesized oligodeoxynucleotide-based antagonist, HJ901, which competitively binds to TLR7/9, may be associated with the downregulation of the NF-κB and JAK2-STAT3 signaling pathways and provide rationale for treating ABC-DLBCL patients with the MyD88 L265P mutation.

A 60-year-old man was admitted for ground glass opacity in the lower lung field and mediastinal lymphadenopathy. Blood tests revealed elevated serum IgM levels, and the urine test detected Bence-Jones protein. Surgical biopsy from the mediastinal lymph node and lung showed small lymphocytes and plasma cells between follicles, and AL kappa amyloid deposition. Genetic examination detected MYD88 L265P mutation. Our diagnosis was lymphoplasmacytic lymphoma (LPL), involving the mediastinum and the lung, followed by amyloidosis. Mutation analysis, in addition to conventional histological evaluation, was useful for a precise diagnosis.

Observation is recommended for patients without immunoglobulin M (IgM)-related complications and/or symptoms related to bone marrow or extramedullary lymphoplasmacytic involvement.2 Asymptomatic IgM monoclonal gammopathy encompasses two clinicopathological entities with a distinct risk of progression to symptomatic WM: IgM monoclonal gammopathy of undetermined significance (IgM MGUS) and smouldering WM (SWM). In their paper, Zanwar I et al i .11 focussed on patients with SWM with the aim of identifying risk factors for early progression to symptomatic WM. Interestingly, they were able to identify a subset of patients (30% of patients with the two variables available) with a high risk of progression to symptomatic WM (median TTP 2-4 years). Zanwar I et al i .11 report that patients with SWM represent one-fifth of patients with WM. [Extracted from the article]

Summary: IgM monoclonal gammopathies of undetermined significance (IgM MGUS) are associated with a risk of progression to Waldenström macroglobulinaemia (WM) or other lymphoproliferative disorders (LPD) of 1–2% per year. We analysed 176 consecutive patients with IgM MGUS to evaluate risk factors for progression. With a median follow‐up of 83 months (1214 person‐years), 15 patients (8·5%) progressed to WM (n = 14) or marginal zone lymphoma (n = 1). The rate of progression was 1·32% per year (95% confidence interval [CI] 0·80–2·20). The serum monoclonal protein concentration and the MYD88 mutation were independent risk factors for progression (Hazard ratio [HR] 23·3, 95% CI 2·0–273·3, P = 0·012 and HR 24·4, 95% CI 2·2–275·3, P = 0·010, respectively). The cumulative incidence of progression, while considering death as a competing event, was 11·6% at 5 years and 38·0% at 10 years in MYD88‐mutated patients with a serum monoclonal protein of 10 g/l or higher, as compared with 0% at 5 years and 1·1% at 10 years for patients with none or one risk factor. This risk‐stratification model is able to identify a subset of patients with IgM MGUS at high risk of progression to WM or LPD who deserve a lifelong follow‐up. [ABSTRACT FROM AUTHOR]

MYD88 mutation has been reported in various lymphomas, specifically in lymphoplasmacytic lymphoma. Yet, the mutation has not been reported in primary follicular lymphoma. Here, we present a 62-year-old male with follicular lymphoma who had an MYD88 L265P somatic mutation and monoclonal IgM gammopathy. He received four cycles of R-CHOP immunochemotherapy. Interim PET/CT evaluation indicated a state of stable disease (SD). Neither did serum IgM remarkably drop. He was then given a bortezomib-contained regimen which significantly reduced the level of serum IgM. To the best of our knowledge, this is the first report of follicular lymphoma with monoclonal IgM and MYD88 L265P mutation. The present case indicated bortezomib may benefit these patients. [ABSTRACT FROM AUTHOR]

This study is to retrospectively evaluate the prevalence of MYD88 and CD79B mutations and the clinicopathologic characteristics of patients with primary diffuse large B cell lymphoma (DLBCL) of the female genital tract and breast. The characteristics, treatments, and outcomes of 19 patients diagnosed with primary DLBCL of the female genital tract and breast, who had formalin-fixed and paraffin-embedded tissues obtained from diagnostic samples diagnosed between January 2004 and June 2016, were analyzed retrospectively. Nineteen female patients (7 with primary breast and 12 with primary female genital tract DLBCL) were included in this retrospective study. Eleven patients (57.9%) carried a MYD88 mutation, including 10 with MYD8 L265P and 1 with the MYD88 L265S mutation. Seven patients (36.8%) harbored a CD79B mutation, which included two cases with CD79B Y196H, two cases with CD79B Y196N, one case with CD79B Y196D, one case with CD79B Y196F, and one case with CD79B Y196X. Four cases had both MYD88 and CD79B mutations. The clinicopathologic parameters, progression-free survival (PFS), and overall survival (OS) of the MYD88 mutation-carrying group were not significantly different from those of the MYD88 wild-type group except for higher LDH levels. Six patients received cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP), while 13 patients received rituximab plus CHOP, and 13 patients received central nervous system prophylaxis. The median OS and PFS were 73 and 56 months, respectively. Patients with primary breast and primary female genital tract DLBCL have a high frequency of MYD88 and CD79B mutations. The presence of these mutations does not affect survival but may offer additional therapeutic options. [ABSTRACT FROM AUTHOR]

Symptomatic hyperviscosity is a common clinical manifestation in patients with Waldenström macroglobulinaemia ( WM) and high serum IgM levels. Prompt intervention is required to prevent catastrophic events, such as retinal or central nervous system bleeding. Identifying patients at high risk of symptomatic hyperviscosity might support the decision to treat asymptomatic patients before irreversible damage occurs. We carried out a large retrospective study in 825 newly diagnosed WM patients, of who 113 (14%) developed symptomatic hyperviscosity. The median serum IgM level at the time of symptomatic hyperviscosity was 61·8 g/l (range 31-124 g/l). Forty-four patients (36%) had symptomatic hyperviscosity at the time of WM diagnosis. A serum IgM level >60 g/l at diagnosis was associated with a median time to symptomatic hyperviscosity of 3 months, whereas the median time for patients with serum IgM level of 50·01-60 g/l was approximately 3 years. Adjusting for other clinical factors, the odds of developing symptomatic hyperviscosity were 370-fold higher with serum IgM levels >60 g/l, and showed an association with CXCR4 mutational status. Symptomatic hyperviscosity did not impact overall survival ( P = 0·12). The findings support the use of serum IgM level >60 g/l as a criterion for initiation of therapy in an otherwise asymptomatic WM patient. [ABSTRACT FROM AUTHOR]

The article highlights the recognition approach of B cell lymphoproliferative disorders in the bone marrow trephine biopsies. It presents the pathological characteristics to establish a diagnostic algorithm for better diagnosis treatment on bone marrow trephine biopsies; and also mentions the findings of patients who were diagnosed as plasmacytic and plasmacytoid lymphomas (LPL), WM, chronic lymphocytic leukaemia (CLL), with IgM paraproteinaemia.

The article discusses a study which examined the prevalence of MYD88 L265P somatic mutation in patients with immunoglobulin M (IgM) monoclonal gammopathy of undetermined significance (MGUS) and smouldering Waldenstrom macroglobulinemia (WM). Topics discussed include the use of polymerase chain reaction (PCR) technology to analyze mutation from DNA collected from bone marrow slides, the overall survival of the patients, and the high prevalence of MYD88 L265P mutation in WM and SWM patients.

A 61-year-old female was referred to our hospital because of pancytopenia and febrile neutropenia. On admission, computed tomography showed mild hepatosplenomegaly and intra-abdominal abscess formation in the right pelvic region; however, no lymphadenopathy was found. Bone marrow (BM) examination showed severe fibrosis by silver staining. Several small- to medium-sized lymphocytes with a constriction in the nuclei were observed, exhibiting CD3 (-), CD10 (-), CD20 (+), BCL-2 (+-), and CD138 (+-). Genetic testing revealed that BM cells were positive for MYD88 mutation and positive for IgH rearrangement, whereas neither JAK2 nor CALR mutation was positive. A diagnosis of BM infiltration of lymphoplasmacytic lymphoma (LPL) was made. Rituximab monotherapy was administered once a week for four times. BM examination 4 weeks after the end of treatment showed that lymphoma cells had disappeared and that myelofibrosis had been almost gone. The MYD88 mutation of BM turned out to be negative at that moment.

A 75-year-old man who had lymphadenopathy was admitted to our hospital. Histopathological examination of cervical lymph node biopsy specimens showed diffuse proliferation of lymphoma cells with large nuclei. In immunohistochemistry, the lymphoma cells were positive for CD5, CD10, CD20, BCL2, BCL6, and MYC. The patient was diagnosed with CD5- and CD10-positive diffuse large B-cell lymphoma (DLBCL). MYD88 L265P mutations have been detected in DLBCL. Partial response was achieved after six courses of R-THP-COP therapy. However, the patient died because of disease progression 18 months after the diagnosis. On autopsy, lymphoma cells were found in the lymph nodes throughout the body, central nervous system, adrenals, and skin. CD5- and CD10-positive DLBCL account for 0.5-1% of DLBCL cases and have a very poor disease prognosis. This is a rare case of CD5- and CD10-positive DLBCL with MYC and BCL2 expressions harboring MYD88 L265P mutation.

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. [ABSTRACT FROM AUTHOR]

The article discusses a study on the link of MYD88 (L265P) mutation to poor prognosis and high risk of progression in primary central nervous system lymphoma (PCNSL) patients. Topics covered include the related link of MYD88 mutations to unfavourable outcome of diffuse large B cell lymphoma (DLBCL) and the importance of clinical sequencing in improving prognostic algorithms of PCNSL. Also noted are the possible alternative treatment regimens for PCNSL patients with MYD88 L265P mutation.

Bing-Neel syndrome (BNS), a rare neurological syndrome associated with Waldenström macroglobulinaemia (WM), is a direct involvement of the central nervous system by lymphoplasmacytoid cells characterized with an adverse prognostic. The MYD88 L265P mutation has been identified in the vast majority of patients with WM. The diagnosis of BNS is often challenging because of the variety of clinical presentations associated with difficult histological techniques. We hypothesized that identification of MYD88 L265P mutation in the cerebrospinal fluid (CSF) would contribute to the diagnosis of BNS in addition to imaging, flow cytometry and cytology. We identified MYD88 L265P mutation in the CSF and the bone marrow of all cases of BNS using quantitative polymerase chain reaction q PCR and Sanger sequencing. Copy neutral loss of heterozygosity including MYD88 was observed in one case. No mutation of CXCR4, CD79A and CD79B was observed in parallel. We further showed that monitoring the quantitative expression of MYD88 L265P mutation might be a useful molecular tool to monitor response to chemotherapy using q PCR. In conclusion, identification of MYD88 L265P mutation might be a new molecular-based biomarker tool to add to the diagnostic and monitoring armamentarium for BNS. [ABSTRACT FROM AUTHOR]

A 60-year-old man was admitted for ground glass opacity in the lower lung field and mediastinal lymphadenopathy. Blood tests revealed elevated serum IgM levels, and the urine test detected Bence-Jones protein. Surgical biopsy from the mediastinal lymph node and lung showed small lymphocytes and plasma cells between follicles, and AL kappa amyloid deposition. Genetic examination detected MYD88 L265P mutation. Our diagnosis was lymphoplasmacytic lymphoma (LPL), involving the mediastinum and the lung, followed by amyloidosis. Mutation analysis, in addition to conventional histological evaluation, was useful for a precise diagnosis. [ABSTRACT FROM AUTHOR]

Bing-Neel syndrome (BNS), which presents with a variety of neurological complications, is a rare manifestation of the lymphoplasmacytic lymphoma (LPL) and is characterized by the infiltration of LPL cells into the central nervous system. In this study, we report the case of a patient with BNS, which was confirmed by detecting MYD88 L265P mutation in the cerebrospinal fluid (CSF) cells. A 74-year-old patient was diagnosed with IgG-variant LPL. He achieved a very good partial response to the treatment with rituximab and bendamustine (RB) and was stable for over 5 years, when presenting a slowly progressive motor deficit in the lower limbs. It was difficult to confirm BNS from morphological analysis of the CSF cells. After detecting MYD88 L265P mutation in the CSF cells, he was subsequently diagnosed with BNS and treated with RB and intrathecal chemotherapy, resulting in rapid clinical improvement. With the onset of neurological manifestation during the clinical course of LPL, the detection of MYD88 L265P mutation in the CSF cells could be helpful for the diagnosis and management of BNS.

Diffuse large B cell lymphoma (DLBCL) is associated with aggressive clinical cases and poor prognosis despite recent advances in disease treatment. In activated B-cell-like (ABC)-DLBCL, the most severe damaged signaling pathways converge to aberrantly activate the Toll-like receptor (TLR) 7/9/MyD88 pathways, leading to the avoidance of cell death and resistance to chemotherapy. A gain of function mutation in MyD88 (MyD88 L265P) enhanced the NF-κB and JAK-STAT signaling pathways and was associated with dysregulation of TLR signaling in the pathogenesis of ABC-DLBCL. Therefore, inhibition of the TLR signaling network may improve clinical outcomes. In this study, we designed a de novo synthesized oligodeoxynucleotide-based antagonist of TLR7 and TLR9, referred to as HJ901, which competitively binds to TLR7/9. We profiled HJ901 inhibition in various DLBCL cell lines and verified tumor suppression in a xenograft mouse model. We found that HJ901 treatment significantly reduced TLR7- and TLR9-mediated cell proliferation and cytokine production in a time- and dose-dependent manner in various DLBCL cell lines expressing the MyD88 L265P mutation. Moreover, HJ901 prevented tumor growth and downregulated the NF-κB and JAK2-STAT3 signaling pathways in a DLBCL xenograft mouse model with the MyD88 L265P mutation. These results reveal that the anti-tumor effects of the synthesized oligodeoxynucleotide-based antagonist, HJ901, which competitively binds to TLR7/9, may be associated with the downregulation of the NF-κB and JAK2-STAT3 signaling pathways and provide rationale for treating ABC-DLBCL patients with the MyD88 L265P mutation., (Copyright © 2020 An, Zhu, Li, Wu, Zang, Lv, Qiao, Huang, Shao, Cui, Liu and Chen.)

Background Recent genetic analysis of primary central nervous system lymphoma (PCNSL) showed that the MyD88 L265P mutation, which is related to NF-κB signaling, was a genetic hallmark for PCNSL; thus it could serve as a genetic marker for diagnosis and a potential target for molecular therapy. However, the role of the MyD88 mutation in PCNSL has not been defined. In this study, we investigated the role of the MyD88 mutation and clinical features of PCNSL-treated patients at several institutions to determine its significance as a prognostic factor. Methods Forty-one PCNSL (diffuse large B-cell type) patients from 8 institutions were included in this study. Their median age was 68 years; median follow-up was 26.7 months; median overall survival was 26.7 months; and their 1-year, 3-year, and 5-year survival rates were 75.6%, 58.5%, and 43.9%, respectively. Deoxyribonucleic acid was extracted from frozen tissue, and the MyD88 L265P mutation was evaluated by polymerase chain reaction and direct sequencing. Results The MyD88 L265P mutation was found in 61.0% (25/41) of cases. Kaplan-Meier analysis revealed that neither MyD88 L265P mutation nor age >65 years alone significantly predicted overall survival relative to MyD88 wild type and age <65. The MyD88 L265P mutation was predominantly present in patients aged >65 years. Among age >65 patients, the MyD88 L265P mutation portended a worse overall survival compared with the MyD88 wild type (11.5 vs. 56.2 months P < 0.04). Conclusion The MyD88 L265P mutation predicted a poor prognosis in elderly PCNSL patients. A new tailor-made treatment strategy might be needed for these patients. [ABSTRACT FROM AUTHOR]

Introduction: An IgM monoclonal gammopathy points to a diagnosis of Waldenstrom's Macroglobulinemia. Other B lymphoproliferatives disorders should be ruled out but the limits are sometimes difficult to define. The discovery of the L265P mutation of the MYD88 gene simplified potentially the situation., Population and Methods: 383 patients of the Jules Bordet Institute with an IgM level above 2 g/L were reviewed. For the 49 who had a monoclonal peak, we analysed the underlying pathology in termes of general, clinical and biological characteristics. We checked if the MYD88 mutation had been detected. The overall survival rate was studied., Results: 5 histological groups were identified: Waldenstrom's Macroglobulinemia (MW, N = 27), lymphoplasmacytic lymphoma (LLP, N = 10), marginal zone lymphoma (LMZ, N = 7), monoclonal gammopathy of unknown significance and multiple myeloma (MGUS/MM, N = 5). The MW group was compared to the other groups. Regarding biological characteristics, the IgM level upon diagnosis was statistically higher in the MW group with a median level at 19.5 g/L (2.3-101 g/L) (p-value = 0,0001). Concerning the clinical characteristics, a splenomegaly was more frequent in the LMZ group (p-value = 0,04). The L265P mutation of the MYD88 gene was found in 77 % of patients in the MW group, 60 % of patients in the LLP group and 67 % in the LMZ group (p-value = 0,38). For the 49 patients, the 10-yearoverall survival was 85 % (CI 95 %, 67 % to 94 %) and the 15-year-overall survival was 65 % (CI 95 %, 41 % to 81 %)., Conclusion: A monoclonal IgM peak suggests a MW but other B lymphoproliferatives disorders should be excluded. Even if the L265P mutation is frequent in the LLP/MW, it is not specific. A precise diagnosis requires collating clinical, histological, immunophenotypical and genetical data.