Elena Kryukova

Flow cytometry in immunoglobulin light chain amyloidosis: Short review.

Flow cytometry (FCM) has found its application in clinical diagnosis and evaluation of monoclonal gammopathies (MG). Although, research has been mainly focused on multiple myeloma (MM), nowadays FCM becomes to be potential tool in the field of AL amyloidosis. Clonal plasma cells identification and specific phenotype profile detection is important for diagnosis, monitoring and prognosis of AL amyloidosis. Therefore, FCM could be a perspective method for study not only MM but also AL amyloidosis. This review provides an overview and possibilities of FCM application in AL amyloidosis.

Nestin expression throughout multistep pathogenesis of multiple myeloma

The stem cell marker nestin (NES) is found in dividing cells of developing and regenerating tissues. Upon terminal differentiation, NES expression is diminished but may be re‐expressed following injury or in cancer. Surprisingly, we recently confirmed NES as a tumour‐specific marker for mature CD138+38+ plasma cells (PC) in multiple myeloma (MM). The present study analysed NES expression throughout the spectrum of MM developmental stages, starting with individuals with no haematological malignancy, through monoclonal gammopathy of undetermined significance (MGUS) and MM to plasma cell leukaemia (PCL) and MM cell lines. NES was analysed in bone marrow PC of 163 MM, four PCL and nine MGUS patients, 10 individuals with no haematological malignancy and 6 myeloma cell lines (OPM‐2, RPMI‐8226, MOLP‐8, U‐266, EJM, NCI‐H929) by flow cytometry and/or real‐time polymerase chain reaction or immunochemistry. We observed a tendency of increased NES expression in parallel with disease progression. NES was evaluated as a reliable marker for accurate discrimination between MM patients and the control group. High NES levels were strongly associated with the presence of 1q21 gain. For the first time, NES was demonstrated to predict worse response to conventional therapy/novel agents. These results suggest that NES might become a useful clinical parameter with an important role in MM pathogenesis.

Centrosome amplification and clonal evolution in multiple myeloma: Short review

Multiple myeloma (MM) is composed of an array of multiple clones, each potentially associated with different clinical behavior. Previous studies focused on clinical implication of centrosome amplification (CA) in MM show contradictory results. It seems that the role of CA as well as CA formation in MM differ from other malignancies. This has brought about a question about the role of CA positive clone which is--is it going to be a more aggressive clone evolutionally arising under pressure of negative conditions or can CA serve as a marker of cell abnormality and lead to cell death and further elimination of this damaged subpopulation? This current review is devoted to the discussion of the existence of MM subclones with centrosome amplification (CA), its evolutionary behaviour within intraclonal heterogeneity as well as its potential impact on the disease progression and MM treatment.

Biobanking strategy and sample preprocessing for integrative research in monoclonal gammopathies

Aims Some types of monoclonal gammopathies are typified by a very limited availability of aberrant cells. Modern research use high throughput technologies and an integrated approach for detailed characterisation of abnormal cells. This strategy requires relatively high amounts of starting material which cannot be obtained from every diagnosis without causing inconvenience to the patient. The aim of this methodological paper is to reflect our long experience with laboratory work and describe the best protocols for sample collection, sorting and further preprocessing in terms of the available number of cells and intended downstream application in monoclonal gammopathies research. Potential pitfalls are also discussed. Methods Comparison and optimisation of freezing and sorting protocols for plasma cells in monoclonal gammopathies, followed by testing of various nucleic acid isolation and amplification techniques to establish a guideline for sample processing in haemato-oncology research. Results We show the average numbers of aberrant cells that can be obtained from various monoclonal gammopathies (monoclonal gammopathy of undetermined significance/light chain amyloidosis/multiple myeloma (MM)/MM circulating plasma cells/ minimal residual disease MM—10 123/22 846/305 501/68 641/4000 aberrant plasma cells of 48/30/10/16/37×106 bone marrow mononuclear cells) and the expected yield of nucleic acids provided from multiple isolation kits (DNA/RNA yield from 1 to 200×103 cells was 2.14–427/0.12–123 ng). Conclusions Tested kits for parallel isolation deliver outputs comparable with kits specialised for just one type of molecule. We also present our positive experience with the whole genome amplification method, which can serve as a very powerful tool to gain complex information from a very small cell population.

Proteasome inhibitors in AL amyloidosis: focus on mechanism of action and clinical activity.

Proteasome inhibitors are the backbone in the treatment of multiple myeloma with 3 of its representatives (bortezomib, carfilzomib, and ixazomib) having already been approved. There is a different situation altogether in the treatment of amyloid light chain (AL) amyloidosis where owing to the rarity of this entity neither of these drugs has currently gained approval. Amyloid light chain plasma cells are possibly more vulnerable to bortezomib than myeloma plasmocytes because of a slightly distinct mechanism of action, which is described in depth in this manuscript. Bortezomib is highly active and rapidly effective as a single agent and even more potent in combination with dexamethasone and alkylators. Bortezomib‐based regimens have become a standard part of the initial treatment of AL amyloidosis in the majority of centers. We have reviewed all available data on bortezomib in various combinations and settings. Carfilzomib seems to be effective but also toxic in these fragile patients with a high rate of cardiac events. Oral ixazomib has shown a surprisingly high efficacy with manageable toxicity and has received the Food and Drug Administration Breakthrough Therapy designation in 2014 for relapsed AL amyloidosis patients. In this review we have comprehensively described the current available knowledge of these 3 proteasome inhibitors and their use in AL amyloidosis.

Waldenström′s macroglobulinemia: Two malignant clones in a monoclonal disease? Molecular background and clinical reflection

Waldenström′s macroglobulinemia (WM) is a complex disease characterized by apparent morphological heterogeneity within the malignant clonal cells representing a continuum of small lymphocytes, plasmacytoid lymphocytes, and plasma cells. At the molecular level, the neoplastic B cell–derived clone has undergone somatic hypermutation, but not isotype switching, and retains the capability of plasmacytic differentiation. Although by classical definition, WM is formed by monoclonal expansion, long‐lived clonal B lymphocytes are of heterogeneous origin. Even more, according to current opinion, plasma cells also conform certain population with pathogenic and clinical significance. In this article, we review the recent advances in the WM clonal architecture, briefly describe B‐cell development during which the molecular changes lead to the malignant transformation and mainly focus on differences between two principal B‐lineage clones, including analysis of their genome and transcriptome profiles, as well as immunophenotype features. We assume that the correct identification of a number of specific immunophenotypic molecular and expression alterations leading to proper aberrant clone detection can help to guide patient monitoring throughout treatment and successfully implement therapy strategies directed against both B‐ and plasma cell tumor WM clones.