Waldenström Macroglobulinemia: Mechanisms of Disease Progression and Current Therapies

GLI3 Is Required for M2 Macrophage Polarization and M2-Mediated Waldenström Macroglobulinemia Growth and Survival

Waldenstrom macroglobulinemia (WM) is a non-Hodgkin B-cell lymphoma, characterized by bone marrow infiltration with plasma cells and lymphocytes. The tumor microenvironment (TME) plays an important role in mediating WM cell biology, but the effects of macrophages on WM biology remains unclear. Here, we investigated the effects of macrophages on WM growth and survival and identified a novel role for transcription factor GLI3 in macrophage polarization. We found that co-culture of M0 and M2 macrophages promoted WM cell growth and survival, and co-culture WM cells with M0 macrophages induced M2-like phenotypes. Interestingly, GLI3 expression was induced in M2 macrophages (not M1), leading us to perform analysis of macrophages from mice lacking Gli3 in myeloid cells (M-Gli3-/- mice). A subset of differentially expressed genes implicated a role for GLI3 in macrophage polarization. Macrophages from M-Gli3-/- mice did not induce WM cell proliferation and reduced survival compared to M2 macrophages from WT mice. In addition, in vitro polarization of M0 macrophages from M-Gli3-/- was not able to induce M2 markers such as CD163, despite inducing iNos expression (M1 marker). Taken together, these results suggest a role for M2 macrophages in promoting WM cell growth and identify GLI3 as a modulator of macrophage polarization.

In-depth molecular analysis of lymphomas with lymphoplasmacytic differentiation may provide more precise diagnosis and rational treatment allocation

We performed a molecular analysis of formalin-fixed paraffin embedded and decalcified bone marrow trephine biopsies of 41 patients with a B-cell disorder with lymphoplasmacytic differentiation to enable a more precise diagnosis and to describe potentially prognostic and therapeutic relevant mutations. Analysis was performed with a commercially available next-generation sequencing (NGS) lymphoma panel (Lymphoma Solution, SophiaGenetics). Results were correlated with clinical and pathological parameters. Our group covered a spectrum of B-cell disorders with plasmacytic differentiation ranging from Waldenstroem's macroglobulinemia (WM), to small-B-cell lymphomas with plasmacytic differentiation (SBCL-PC) to IgM myeloma (MM). The most helpful diagnostic criteria included morphology and immuno-phenotype as a prerequisite for the interpretation of molecular analysis. MYD88 mutation was present in nearly all WM, but also in 50% of SBCL-PCs, while MM were consistently negative. Driver mutations, such as TP53, were already detectable early in the course of the respective diseases indicating a higher risk of progression, transformation, and reduced progression-free survival. In addition, we report on a novel BIRC3 frameshift mutation in one case of a progressive WM. Our data indicate that patients with LPL/WM might benefit from thorough pathological work-up and detailed molecular analysis in terms of precise diagnosis and targeted treatment allocation.

A Case of Type 1 Cryoglobulinemia With Lymphoplasmacytic Lymphoma and Dry Gangrene

Lymphoplasmacytic lymphoma (LPL) is an uncommon condition, accounting for only 2% of all non-Hodgkin's lymphoma cases. Individuals with LPL face the risk of vascular blockage when associated with type I cryoglobulinemia, leading to related symptoms. Until now, no instances of LPL with dry gangrene have been documented. However, we present a rare case involving LPL accompanied by dry gangrene in both the right upper extremity (RUE) and left lower extremity (LLE). The patient was effectively managed using a combination of chemotherapy, steroids, plasmapheresis, and salvage surgery.

Broadening the horizon: potential applications of CAR-T cells beyond current indications

Engineering immune cells to treat hematological malignancies has been a major focus of research since the first resounding successes of CAR-T-cell therapies in B-ALL. Several diseases can now be treated in highly therapy-refractory or relapsed conditions. Currently, a number of CD19- or BCMA-specific CAR-T-cell therapies are approved for acute lymphoblastic leukemia (ALL), diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), multiple myeloma (MM), and follicular lymphoma (FL). The implementation of these therapies has significantly improved patient outcome and survival even in cases with previously very poor prognosis. In this comprehensive review, we present the current state of research, recent innovations, and the applications of CAR-T-cell therapy in a selected group of hematologic malignancies. We focus on B- and T-cell malignancies, including the entities of cutaneous and peripheral T-cell lymphoma (T-ALL, PTCL, CTCL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML), chronic lymphocytic leukemia (CLL), classical Hodgkin-Lymphoma (HL), Burkitt-Lymphoma (BL), hairy cell leukemia (HCL), and Waldenström's macroglobulinemia (WM). While these diseases are highly heterogenous, we highlight several similarly used approaches (combination with established therapeutics, target depletion on healthy cells), targets used in multiple diseases (CD30, CD38, TRBC1/2), and unique features that require individualized approaches. Furthermore, we focus on current limitations of CAR-T-cell therapy in individual diseases and entities such as immunocompromising tumor microenvironment (TME), risk of on-target-off-tumor effects, and differences in the occurrence of adverse events. Finally, we present an outlook into novel innovations in CAR-T-cell engineering like the use of artificial intelligence and the future role of CAR-T cells in therapy regimens in everyday clinical practice.

Signal Pathways in Cancer

Cancer is a major health-threatening disease and is the second leading cause of death worldwide; the prevention and treatment of cancer remains one of the most challenging problems clinically [...].