Project description:To gain further insights into the role of the transcriptome deregulation in the transition from a normal plasma cell (NPC) to a clonal PC and from an indolent clonal PC to a malignant PC, we performed gene expression profiling in 20 patients with MGUS, 33 with high-risk SMM and 41 with MM. The analysis showed that 126 genes were differentially expressed in MGUS, SMM and MM as compared to NPC. Interestingly, 17 and 9 out of the 126 significant differentially expressed genes were small nucleolar RNA molecules (snoRNA) and zinc finger proteins. GADD45A was the most significant up-regulated gene in clonal PC compared to NPC. Several proapoptotic genes (AKT1 and AKT2) were downregulated and antiapoptotic genes (APAF1 and BCL2L1) were upregulated in MM, both symptomatic and asymptomatic, compared to MGUS. Myc mediated apoptosis signaling is one of the top canonical pathways differentiating the asymptomatic and symptomatic myeloma. When we looked for those genes progressively modulated through the evolving stages of monoclonal gammopathies, eight snoRNA showed a progressive increase while APAF1, VCAN and MEGF9 exhibited a progressive downregulation in the transition from MGUS to SMM and to MM. In conclusion, our data show that although MGUS, SMM and MM are not clearly distinguishable groups according to their GEP, several signaling pathways and genes were significant deregulated in the different steps of transformation process. Bone marrow (BM) samples were obtained from 20 patients with MGUS, 33 with high-risk SMM and 41 with MM. All samples corresponded to newly diagnosed untreated patients. To avoid misclassification or overlapping entities we decided to focus on MGUS patients with more than two years of stable follow-up. Samples were classified according to the International Myeloma Working Group criteria. The criteria for defining high-risk SMM has been described previously. In addition, five healthy donors were also included in order to relate the deregulation of gene expression profiling of clonal populations to normal condition. The study was approved by the research ethic committees of all participating centers and written informed consent was obtained from all patients in accordance with the Helsinki Declaration. The main clinical and laboratory characteristics of these patients are shown in Supplementary Table 1.

Project description:Tumor immune microenvironmental alterations occur early in multiple myeloma (MM) development. In this study, we aim to systematically characterize the tumor immune microenvironment (TME) and the tumor-immune interactions from precursor stages, i.e., monoclonal gammopathy of undetermined significance (MGUS) and smoldering MM (SMM), to newly diagnosed MM, comparing these to healthy donors. CIBERSORT analysis revealed proportions of 27 cell types, including 10 innate immune cells (monocytes, M0/M1/M2 macrophages, resting/activated dendritic cells, resting/activated mast cells, eosinophils, and neutrophils), 7 T cell subsets (CD8+ T cells, naive CD4+ T cells, resting/activated memory CD4+ T cells, follicular helper T cells, regulatory T cells, and gamma delta T cells), resting/activated NK cells, naive B cells, memory B cells, plasma cells, myeloma plasma cells, memory plasma cells, osteoblasts, osteoclasts and adipocytes. We removed plasma cells (PC) from the 100% total cell proportions to avoid bias resulting from different tumor burdens. We found that the proportions of neutrophils, mast cells, and monocytes account for the majority of innate immune cells and were decreased in NDMM and its precursor stages when compared with NBM. We noticed a significant abundance of M2 macrophages in NDMM, but not in the precursor stages. The proportion of CD8+ T cells was increased at the SMM and MM stages, and the proportion of activated memory CD4+ T cells continued to decrease from NBM to MGUS, SMM, and MM. We performed correlation analysis of immune cell proportions with the time of progression of MGUS and SMM patients. We observed neutrophil proportions were negatively correlated with the time to progression in SMM patients, indicating more neutrophils predict inferior outcomes for SMM patients. However, in NDMM patients, we observed that the neutrophil percentage was decreased in patients with high-risk status based on the 70-gene Prognostic Risk Score (GEP-70) or at stage III of International Staging System (ISS), and patients with high proportions of neutrophils had a significantly superior overall survival (OS) and event-free survival (EFS). For T cell populations, we observed that the proportions of CD8+ T cells were negatively correlated with the time of progression in SMM patients and the γδ T cells were positively correlated. We observed the proportions of γδ T cells were also positively correlated with the time of progression in MGUS patients. Consistent with the time-to-progression data, high-risk SMM patients showed higher proportions of CD8+ T cells and lower proportions of naïve CD4+ T cells and γδ T cells.

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