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Extramedullary disease of multiple myeloma (EM) remains a treatment challenge even in the era of new drugs. While many reports analyzing various aspects of EM have been published, mechanism of EM development has not been clarified yet. This review summarizes current knowledge about this clinical entity, including its history, diagnostics, imaging methods, incidence, prognosis, current treatment options, risk factors and known molecular mechanisms that might be involved in pathogenesis of EM.

Background Multiple myeloma (MM) is the second most common hematological malignancy of the elderly. The bone marrow is infiltrated by malignant plasma cells. MM may progress into so-called extramedullary disease (EMD). EMD occurs when a subclone of clonal plasma cells migrates out of the bone marrow and infiltrates soft tissues. Aims We focused on the analysis of low molecular weight molecules in peripheral blood of 20 MM and 20 EMD patients using MALDI-TOF mass spectrometry to create a diagnostic tool based on prediction by artificial neural network, which should distinguish different groups of diseases. Methods Matrix-Assisted Laser Desorption/Ionization Time-of Flight Mass Spectrometry (MALDI-TOF MS) has become an indispensable research tool, which is used for analysis of biomolecules and various organic molecules. Artificial Neural Networks (ANN) are components of artificial intelligence inspired by biological neural networks. Using ANN, we can model complex non-linear systems, as previously published. In our previous study, we recorded mass spectra of MM and healthy donor samples. ANN specifically predicted MM samples with high sensitivity, specificity and accuracy. Results The RStudio was used for statistical analysis, where the data were evaluated using Principal Component Analysis (PCA) and Partial least squares discriminant analysis (PSL-DA). Using MALDI-TOF MS, it was possible to distinguish between samples of MM patients and healthy donors, as well as MM and EMD patients. Informative patterns in mass spectra served as inputs for ANN that specifically distinguished between healthy donors and patients. Conclusion We demonstrated that using MALDI-TOF MS coupled with ANN is a useful tool that can distinguish between healthy donors and patients. Thus, it can be used as a fast alternative to conventional analyses. This study was supported by grants of the Ministry of Health of the Czech Republic, grant nr. NV18-08-00299, AZV 18-03-00203.

Background Plasma cell leukemia (PCL) is a rare and very aggressive plasma cell (PC) disorder characterized by the presence of circulating plasma cells (cPC) in peripheral blood (PB). Dismal outcome of PCL requires early diagnosis with appropriate analytical tools. Development of flow cytometry (FC) together with some newly analysed antigens may reveal some marker affecting the prognosis of PCL patients. Aim Analysis of phenotypic profile of cPC/PCs to find association with clinical outcomes and to evaluate the prognostic value of analyzed markers. Methods Total of 33 primary and secondary PCL patients were investigated. PCs quantity and phenotype profile was analysed by polychromatic FC in PB and bone marrow (BM). Results Flow cytometry is an excellent method for cPCs identification as a significantly higher number was identified by FC than by morphology. Thus FC should be incorporated as a diagnostic method for preventing late diagnosis of PCL. Although the phenotypic profile of both PCLs did not differ too much, with low level of CD19, CD20, CD27, CD28, CD81 and CD117 expression, some heterogeneously expressed antigens (CD44, CD56, CD200, nestin etc.) may contribute to identification of patients with later extramedullary involvement, high risk of progression and shortened survival. Conclusions FC should be incorporated in PCL diagnostics as not only exact method providing number of cPCs, which is surprisingly overcoming morphology assessment. Moreover, PCL phenotype profile could be connected to patient’s diagnosis and possible prognosis as well. Funding Supported by grant AZV NV18-03-00203.

Background Multiple myeloma (MM) is a heterogeneous plasma cell (PC) malignancy. These malignant PC are dependent on the bone marrow (BM) microenvironment. However, a subclone of PCs can escape the BM microenvironment and infiltrate soft tissues and organs in the so-called extramedullary disease (EMD). This subclone may also escape to peripheral blood; if there are more than 20% of circulating PC (cPC), the disease is reclassified as plasma cell leukemia (PCL). All cells in the BM microenvironment release exosomes. Exosomes are small membranous vesicles that originate from internal multivesicular bodies; they are found in all body fluids, including peripheral blood, breast milk, etc. Exosomes are important in intercellular communication, and they have been implicated in disease relapse, resistance to chemotherapy and many other processes important for tumorigenesis. They contain proteins and nucleic acids, such as microRNAs (miRNAs) - short non-coding RNA molecules that are involved in many physiological and pathological processes. Aims The aim of this work was to analyze expression of exosomal miRNAs in BM plasma samples of MM, EMD and PCL patients. Methods Exosomes were isolated using qEV columns. MiRNAs were isolated from exosomes using qEV original Size Exclusion Columns, following miRNA isolation using miRNeasy Micro Kit. For next generation sequencing (NGS), 8 MM, 7 EMD and 8 PCL samples were used. Results from NGS were validated on 40 MM, 25 EMD and 21 PCL samples by RT-qPCR using Taqman Advanced MiRNA Assays. Results NGS analysis showed 1128 different miRNAs that were present in analyzed samples. Out of these, 239 miRNAs were found in at least 8 samples and had more than 1 read per million; thus, they were included in subsequent analysis. Out of these miRNAs, there are 6 miRNAs (p Conclusions Using NGS, we showed that they are differentially expressed exosomal miRNAs between MM, EMD and PCL patients suggesting their role in pathogenesis of these diseases. This work was supported by AZV 17-29343A and AZV 18-003-00203.

We have performed a face to face comparison of all-oral triplet ixazomib, lenalidomide and dexamethasone (IRD) versus lenalidomide and dexamethasone (RD) in patients with relapsed and refractory multiple myeloma (RRMM) in the routine clinical practice. The primary endpoint was progression free survival (PFS), secondary end points included response rates and overall survival (OS).

Great progress achieved in treatment of multiple myeloma (MM) over the past decade changed overall perception of importance of minimal residual disease (MRD) assessment. Since new drugs induce deep responses, MRD must be evaluated using sensitive techniques, such as allele specific PCR (ASO-PCR), next-generation sequencing (NGS) or flow cytometry. MM is a genetically heterogeneous disease characterized by multiple focal lesions in the bone marrow (BM). BM samples are typically used for analysis, but currently an alternative approach called liquid biopsies, which utilize body fluids for analysis of various molecules and cells, is intensively studied. Cell-free DNA as one type of the molecule which can be analyzed using liquid biopsy approach. In our study, patient-specific, clonotypic rearrangement of immunoglobulin heavy chain (IgH) gene, identified in BM samples, was used for qPCR analysis of cfDNA samples from peripheral blood. We demonstrate that dynamics and quantity of patient-specific, clonotypic IgH rearrangement found in cfDNA can predict the outcomes and response of MM patients.