Yang, Zhi Zhang

Abstract IgM MGUS and Waldenstrom Macroglobulinemia (WM) represent a disease spectrum with highly dissimilar therapeutic management ranging from observation to chemoimmunotherapy. The current classification relies solely on clinical features and does not explain the heterogeneity that exists within each of these conditions. To shed light on the biology that may account for the clinical differences, we used bone marrow (BM) CD19+/CD138+ sorted cells and matched BM plasma from 32 patients (pts) (7 IgM MGUS, 25 WM) and 5 healthy controls to perform the first comprehensive multiomics approach including whole exome sequencing, RNA seq, proteomics and metabolomics. Applying principal component analysis to gene expression profiling, most of WM pts clustered together, while a small subset of them grouped separately with MGUS pts, suggesting a biologic dichotomy within WM. The healthy controls formed a distinct group from most WM and MGUS. We then applied a non-negative matrix factorization consensus clustering to the gene expression data and identified three robust clusters. Cluster 1 (C1) included only WM pts, cluster 2 (C2) included both WM and MGUS pts, and cluster 3 (C3) included all controls as well as a small number of WM and MGUS pts. When mutations commonly identified in WM were analyzed, there was no difference among the three groups (excluding controls) in mutation burden of MYD88 L265P and CXCR4. Interestingly, aberrant expression of TNFAIP3 seemed a distinct feature of C1 as deletion of 6q (which encodes for TNFAIP3) and TNFAIP3 mutations were each significantly enriched in C1 (47%) compared to C2 (0%) and C3 (20%; p=0.04). Individual clusters associated with specific transcriptional signature and clinical features. While C1 displayed enrichment of cell growth, downregulation of inflammatory pathways (eg IL6 and IL8 signaling) and aggressive behavior, C2 showed increased inflammatory signaling and cell survival with indolent behavior. C3 had an intermediate feature with combined proliferative and inflammatory signatures. In accordance with the transcriptomic data, the hallmark of C1 was upregulation of proliferation-associated proteins (eg AKT, MAPK) and downregulation of inflammatory proteins (eg IL4, IL10) while the opposite was observed in C2. Once more, C3 confirmed intermediate features with combined upregulation of proliferation and inflammatory proteins. The metabolism was rewired towards fatty acid catabolism in C1, glycolysis in C2 and anabolism in C3. Accordingly, C1 showed undetectable concentration of 3-hydroxybutyric acid as opposed to C2 which had increased levels of malic and lactic acids, as end products of fatty acid oxidation and glycolysis respectively. Those metabolites had intermediate levels in C3. In conclusion, we identified three molecular clusters with distinct clinical, proteomic and metabolomic features, suggesting a potential biologic classification that may have therapeutic implications. Citation Format: Patrizia Mondello, Jonas Paludo, Joseph Novak, Kerstin Wenzl, Shahrzad Jalali, Jordan Krull, Esteban Braggio, Surendra Dasari, Michelle Manske, Jithma Abeykoon, Asher Chanan-Khan, Robert Kyle, Morie Gertz, Zhi Zhang Yang, Anne Novak, Stephen Ansell. Molecular clusters and functional drivers of IgM monoclonal gammopathies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3487.

8538 Background: Follicular lymphoma (FL) is a heterogeneous disease with a variable prognosis. Transformation to an aggressive lymphoma is associated with a poor prognosis. Previous studies have identified tumor microenvironment cells such as CD68+ macrophages, PD-1+ and FOXP3+ cells as prognostic in FL. However, results have been conflicting and infrequently address the risk of transformation. In this study we analyzed various components of the microenvironment and their association with transformation. Methods: Patients with FL that later transformed were identified through Mayo Clinic lymphoma database. Tissue specimens at diagnosis were stained with CD68, CD11c, CD21, CXCL13, FOXP3, PD-1 and CD14 and characterized by pattern of location and semi-quantitative cell content. Time to transformation (TTT) and overall survival (OS) were assessed by Kaplan-Meir analysis. Significant variables were further analyzed by cox proportional hazards model. Results: 58 patients were included with a median TTT of 4.7 years (range, 0.4-20). Presence of CD14+ cells vs absence and their location (follicular vs non-follicular) were associated with shorter TTT (4.5 vs 6.2 yrs., p=0.037 and 3.8 vs 5.9 yrs. p= 0.027, respectively). The quantity of PD-1+ cell content was not associated with TTT or OS. However, localization of PD-1 to the follicle compared to diffuse was associated with a longer TTT (6.1 vs 3.6 yrs. p=0.033) and superior OS (9.7 vs 4.6 yrs. p=0.009). On multivariate analysis, the pattern of CD14 and PD-1 staining remained significantly associated with shorter TTT (Table). Conclusions: In follicular lymphoma, a diffuse pattern of PD-1+ cells is associated with inferior TTT and OS. CD14+ cells localized to the follicle is associated with a shorter TTT. After accounting for FLIPI score, both these factors remained significant. These results identify two independent predictors of the rate of transformation in follicular lymphoma and suggest it is location rather than quantity of CD14+ or PD-1+ cells that influence outcomes. [Table: see text]

Abstract Purpose: Transformation of follicular lymphoma is a critical event associated with a poor prognosis. The role of the tumor microenvironment in previous transformation studies has yielded conflicting results. Experimental Design: To define cell subtypes associated with transformation, we examined tissue specimens at diagnosis from patients with follicular lymphoma that later transformed and, using immunohistochemistry (IHC), stained for CD68, CD11c, CD21, CXCL13, FOXP3, PD1, and CD14. Cell content and the pattern of expression were evaluated. Those identified as significantly associated with time to transformation (TTT) and overall survival (OS) were further characterized by flow cytometry and multicolor IHC. Results: Of note, 58 patients were analyzed with median TTT of 4.7 years. The pattern of PD1+ and CD14+ cells rather than the quantity of cells was predictive of clinical outcomes. On multivariate analysis, including the follicular lymphoma international prognostic index score, CD14+ cells localized in the follicle were associated with a shorter TTT (HR, 3.0; P = 0.004). PD1+ cells with diffuse staining were associated with a shorter TTT (HR, 1.9; P = 0.045) and inferior OS (HR, 2.5; P = 0.012). Multicolor IHC and flow cytometry identified CD14+ cells as follicular dendritic cells (FDC), whereas PD1+ cells represented two separate populations, TFH and exhausted T cells. Conclusion: These results identify the presence of PD1+ T cells and CD14+ FDC as independent predictors of transformation in follicular lymphoma. Clin Cancer Res; 20(11); 2862–72. ©2014 AACR.

Abstract Cytokines within the tumor microenvironment play an important role in supporting the growth and survival of B-cell malignancies. One such cytokine, IL-21, promotes the growth of myeloma and Hodgkin lymphoma cells while inducing apoptosis in chronic lymphocytic leukemia. However, the biologic significance of IL-21 has not been examined in Waldenstrom macroglobulinemia (WM), a B-cell lymphoma characterized by elevated serum IgM and a lymphoplasmacytic bone marrow infiltrate. We report here on the presence of IL-21 in the bone marrow of patients with WM and have identified activated T cells as the source of this cytokine. We readily detected the IL-21 receptor on malignant WM B cells and show that IL-21 significantly increases both IgM secretion and cellular proliferation of these cells with no effect on viability. IL-21 rapidly induces phosphorylation of STAT3 in WM cells, and treatment of the WM cell line MWCL-1 with a STAT3 inhibitor abolished the IL-21–mediated increases in cellular proliferation and IgM secretion. IL-21 also increased the expression of known STAT3 targets involved in B-cell differentiation, including BLIMP-1, XBP-1, IL-6, and IL-10. Overall, our data indicate that IL-21 in the bone marrow microenvironment significantly affects the biology of WM tumor cells through a STAT3-dependent mechanism.