Clonal Relationship and Mutation Analysis in Lymphoplasmacytic Lymphoma/Waldenström Macroglobulinemia Associated With Diffuse Large B-cell Lymphoma.

Patients with lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM) occasionally develop diffuse large B-cell lymphoma (DLBCL). This mostly results from LPL/WM transformation, although clonally unrelated DLBCL can also arise. LPL/WM is characterized by activating MYD88L265P (>95%) and CXCR4 mutations (~30%), but the genetic drivers of transformation remain to be identified. Here, in thirteen LPL/WM patients who developed DLBCL, the clonal relationship of LPL and DLBCL together with mutations contributing to transformation were investigated. In 2 LPL/WM patients (15%), high-throughput sequencing of immunoglobulin gene rearrangements showed evidence of >1 clonal B-cell population in LPL tissue biopsies. In the majority of LPL/WM patients, DLBCL presentations were clonally related to the dominant clone in LPL, providing evidence of transformation. However, in 3 patients (23%), DLBCL was clonally unrelated to the major malignant B-cell clone in LPL, of which 2 patients developed de novo DLBCL. In this study cohort, LPL displayed MYD88L265P mutation in 8 out of eleven patients analyzed (73%), while CXCR4 mutations were observed in 6 cases (55%). MYD88WT LPL biopsies present in 3 patients (27%) were characterized by CD79B and TNFAIP3 mutations. Upon transformation, DLBCL acquired novel mutations targeting BTG1, BTG2, CD79B, CARD11, TP53, and PIM1. Together, we demonstrate variable clonal B-cell dynamics in LPL/WM patients developing DLBCL, and the occurrence of clonally unrelated DLBCL in about one-quarter of LPL/WM patients. Moreover, we identified commonly mutated genes upon DLBCL transformation, which together with preserved mutations already present in LPL characterize the mutational landscape of DLBCL occurrences in LPL/WM patients.

A significant proportion of classic Hodgkin lymphoma recurrences represents clonally unrelated second primary lymphoma.

Despite high cure rates in classic Hodgkin lymphoma (cHL), relapses are observed. Whether relapsed cHL represents second primary lymphoma or an underlying T-cell lymphoma (TCL) mimicking cHL is underinvestigated. To analyze the nature of cHL recurrences, in-depth clonality testing of immunoglobulin (Ig) and T-cell receptor (TCR) rearrangements was performed in paired cHL diagnoses and recurrences among 60 patients, supported by targeted mutation analysis of lymphoma-associated genes. Clonal Ig rearrangements were detected by next-generation sequencing (NGS) in 69 of 120 (58%) diagnoses and recurrence samples. The clonal relationship could be established in 34 cases, identifying clonally related relapsed cHL in 24 of 34 patients (71%). Clonally unrelated cHL was observed in 10 of 34 patients (29%) as determined by IG-NGS clonality assessment and confirmed by the identification of predominantly mutually exclusive gene mutations in the paired cHL samples. In recurrences of >2 years, ∼60% of patients with cHL for whom the clonal relationship could be established showed a second primary cHL. Clonal TCR gene rearrangements were identified in 14 of 125 samples (11%), and TCL-associated gene mutations were detected in 7 of 14 samples. Retrospective pathology review with integration of the molecular findings were consistent with an underlying TCL in 5 patients aged >50 years. This study shows that cHL recurrences, especially after 2 years, sometimes represent a new primary cHL or TCL mimicking cHL, as uncovered by NGS-based Ig/TCR clonality testing and gene mutation analysis. Given the significant therapeutic consequences, molecular testing of a presumed relapse in cHL is crucial for subsequent appropriate treatment strategies adapted to the specific lymphoma presentation.

Detection of Second Primary Lymphoma in Late Diffuse Large B-cell Lymphoma Recurrences.

Approximately one-third of patients with diffuse large B-cell lymphoma (DLBCL) relapse and often require salvage chemotherapy followed by autologous stem cell transplantation. In most cases, the clonal relationship between the first diagnosis and subsequent relapse is not assessed, thereby potentially missing the identification of second primary lymphoma. In this study, the clonal relationship of 59 paired DLBCL diagnoses and recurrences was established by next-generation sequencing-based detection of immunoglobulin gene rearrangements. Among 50 patients with interpretable results, 43 patients (86%) developed clonally related relapsed disease. This was observed in 100% of early recurrences (<2 years), 80% of the recurrences with an interval between 2 and 5 years, and 73% of late recurrences (≥5 years). On the other hand, 7 (14%) out of 50 patients displayed different dominant clonotypes in primary DLBCL and clinical recurrences, confirming the occurrence of second primary DLBCL; 37% of DLBCL recurrences that occurred ≥4 years after diagnosis were shown to be second primary lymphomas. The clonally unrelated cases were Epstein-Barr virus positive in 43% of the cases, whereas this was only 5% in the relapsed DLBCL cases. In conclusion, next-generation sequencing-based clonality testing in late recurrences should be considered in routine diagnostics to distinguish relapse from second primary lymphoma, as this latter group of patients with DLBCL may benefit from less-intensive treatment strategies.

Molecular Genetics of Relapsed Diffuse Large B-Cell Lymphoma: Insight into Mechanisms of Therapy Resistance.

The majority of patients with diffuse large B-cell lymphoma (DLBCL) can be treated successfully with a combination of chemotherapy and the monoclonal anti-CD20 antibody rituximab. Nonetheless, approximately one-third of the patients with DLBCL still experience relapse or refractory (R/R) disease after first-line immunochemotherapy. Whole-exome sequencing on large cohorts of primary DLBCL has revealed the mutational landscape of DLBCL, which has provided a framework to define novel prognostic subtypes in DLBCL. Several studies have investigated the genetic alterations specifically associated with R/R DLBCL, thereby uncovering molecular pathways linked to therapy resistance. Here, we summarize the current state of knowledge regarding the genetic alterations that are enriched in R/R DLBCL, and the corresponding pathways affected by these gene mutations. Furthermore, we elaborate on their potential role in mediating therapy resistance, also in connection with findings in other B-cell malignancies, and discuss alternative treatment options. Hence, this review provides a comprehensive overview on the gene lesions and molecular mechanisms underlying R/R DLBCL, which are considered valuable parameters to guide treatment.

QALY-time: experts' view on the use of the quality-adjusted LIFE year in COST-effectiveness analysis in palliative care.

BACKGROUND: The Quality-Adjusted Life Year (QALY) is internationally recognized as standard metric of health outcomes in cost-effectiveness analyses (CEAs) in healthcare. The ongoing debate concerning the appropriateness of its use for decision-making in palliative care has been recently mapped in a review. The aim was to report on and draw conclusions from two expert meetings that reflected on earlier mapped issues in order to reach consensus, and to advise on the QALY's future use in palliative care. METHODS: A nominal group approach was used. In order to facilitate group decision making, three statements regarding the use of the QALY in palliative care were discussed in a structured way. Two groups of international policymakers, healthcare professionals and researchers participated. Data were analysed qualitatively using inductive coding. RESULTS: 1) Most experts agreed that the recommended measurement tool for the QALYs 'Q' component, the EuroQol-5D (EQ-5D), is inappropriate for palliative care. A more sensitive tool, which might be based on the capabilities approach, could be used or developed. 2) Valuation of time should be incorporated in the 'Q' part, leaving the linear clock time in the 'LY' component. 3) Most experts agreed that the QALY, in its current shape, is not suitable for palliative care. CONCLUSIONS: 1) Although the EQ-5D does not suffice, a generic tool is needed for the QALY. As long as no suitable alternative is available, other tools can be used besides or serve as basis for the EQ-5D because of issues in conceptual overlap. 2) Future research should further investigate the valuation of time issue, and how best to integrate it in the 'Q' component. 3) A generic outcome measure of effectiveness is essential to justly allocate healthcare resources. However, experts emphasized, the QALY is and should be one of multiple criteria for choices in the healthcare insurance package.

High frequency of inactivating tetraspanin C D37 mutations in diffuse large B-cell lymphoma at immune-privileged sites.

Tetraspanin CD37 is predominantly expressed on the cell surface of mature B lymphocytes and is currently being studied as novel therapeutic target for B-cell lymphoma. Recently, we demonstrated that loss of CD37 induces spontaneous B-cell lymphoma in Cd37-knockout mice and correlates with inferior survival in patients with diffuse large B-cell lymphoma (DLBCL). Here, CD37 mutation analysis was performed in a cohort of 137 primary DLBCL samples, including 44 primary immune-privileged site-associated DLBCL (IP-DLBCL) samples originating in the testis or central nervous system. CD37 mutations were exclusively identified in IP-DLBCL cases (10/44, 23%) but absent in non-IP-DLBCL cases. The aberrations included 10 missense mutations, 1 deletion, and 3 splice-site CD37 mutations. Modeling and functional analysis of CD37 missense mutations revealed loss of function by impaired CD37 protein expression at the plasma membrane of human lymphoma B cells. This study provides novel insight into the molecular pathogenesis of IP-DLBCL and indicates that anti-CD37 therapies will be more beneficial for DLBCL patients without CD37 mutations.

Towards elucidating the stability, dynamics and architecture of the nucleosome remodeling and deacetylase complex by using quantitative interaction proteomics.

The nucleosome remodeling and deacetylase (NuRD) complex is an evolutionarily conserved chromatin-associated protein complex. Although the subunit composition of the mammalian complex is fairly well characterized, less is known about the stability and dynamics of these interactions. Furthermore, detailed information regarding protein-protein interaction surfaces within the complex is still largely lacking. Here, we show that the NuRD complex interacts with a number of substoichiometric zinc finger-containing proteins. Some of these interactions are salt-sensitive (ZNF512B and SALL4), whereas others (ZMYND8) are not. The stoichiometry of the core subunits is not affected by high salt concentrations, indicating that the core complex is stabilized by hydrophobic interactions. Interestingly, the RBBP4 and RBBP7 proteins are sensitive to high nonionic detergent concentrations during affinity purification. In a subunit exchange assay with stable isotope labeling by amino acids in cell culture (SILAC)-treated nuclear extracts, RBBP4 and RBBP7 were identified as dynamic core subunits of the NuRD complex, consistent with their proposed role as histone chaperones. Finally, using cross-linking MS, we have uncovered novel features of NuRD molecular architecture that complement our affinity purification-MS/MS data. Altogether, these findings extend our understanding of MBD3-NuRD structure and stability. STRUCTURED DIGITAL ABSTRACT: MBD3 physically interacts with ZNF512B, HDAC1, ZMYND8, GATAD2B, SALL4, GATAD2A, ZNF592, MTA3, ZNF687, CDK2AP1, CHD3, ZNF532, HDAC2, MTA2, CHD4, MTA1, KPNA2, CHD5, RBBP4 and RBBP7 by pull down (View interaction) CDK2AP1 physically interacts with MBD3, MTA3, HDAC2, GATAD2A, CHD4, CDK2AP1, MTA2, HDAC1, MTA1, CHD3, GATAD2B, MBD2, RBBP4 and RBBP7 by pull down (View interaction) MBD3 physically interacts with MTA2, MTA3, RBBP4, RBBP7, HDAC2, HDAC1, CHD4, CHD3 and MTA1 by cross-linking study (View interaction).