Background: To study the histological structure and immunohistochemical (IHC) parameters of the plasmacytoma tumour substrate in patients with multiple myeloma (MM). Methods: The study included 21 patients (10 men/11 women) aged 23 to 73 years old with newly diagnosed MM complicated by plasmacytoma. Bone plasmacytoma was diagnosed in 14 patients, and extramedullary plasmacytoma was diagnosed in 7 patients. Plasmacytoma tissue specimens were examined using a LEICA DM4000B microscope. Anti-CD56, anti-CD166, anti-CXCR4, anti-Ki-67, and anti-c-MYC antibodies were used for IHC study of plasmacytoma biopsies. Results: When comparing the morphology of bone and extramedullary plasmacytoma, no significant differences were revealed; however, the substrate of extramedullary plasmacytoma was more often represented by tumour cells with an immature morphology than was the bone plasmacytoma substrate (57.1% vs. 28.6%, respectively). We revealed a significant difference in the expression of CD166 between bone and extramedullary plasmacytoma. The mean values ​​of CD166 expression in bone plasmacytoma cells were significantly higher (36.29 ± 7.61% versus 9.57 ± 8.46%, respectively; p = 0.033) than those in extramedullary plasmacytoma cells. We noticed that in extramedullary plasmacytoma cells, there were higher values for the Ki-67 index than in bone plasmacytoma cells, and this result was independent of cell morphology. Conclusion: The mechanisms involved in the dissemination of tumour plasma cells are currently unexplored. Even in such a small sample, some differences in expression could be identified, which may indicate that different mechanisms lead to the formation of bone and extramedullary plasmacytomas. Specifically, the expression of CD166 in extramedullary plasmacytoma cells was almost 4 times lower than that in bone plasmacytoma cells, which may indicate the involvement of CD166 in the mechanisms of bone destruction. The proliferative activity of extramedullary plasmacytoma cells was shown to be higher than that of bone plasmacytoma cells.

Background. Multiple myeloma complicated by extramedullary plasmacytoma is an unfavorable variant of the disease. It remains unknown what triggers tumor transformation. The review presents literature data on the pathogenesis of extramedullary disease, as well as a clinical example of a comprehensive study of the tumor substrate.Aim. To study the molecular and biological characteristics of the tumor substrate of the bone marrow and extramedullary plasmacytoma using various research methods.Materials and methods. A 55-year-old patient was admitted to National Medical Research Center for Hematology with a diagnosis of multiple myeloma occurring with extramedullary plasmacytoma of the retroperitoneal space. dNA was isolated from samples of different localization (blood plasma, Cd138+ bone marrow cells, plasmacytoma and buccal epithelial cells). The profile of short tandem dNA repeats (STR) from the obtained samples was studied by multiplex polymerase chain reaction followed by fragment analysis. fluorescent in situ hybridization (fISH) of bone marrow Cd138+ cells was performed using various dNA probes. Comparative genomic hybridization on a microarray (arrayCGH) plasmacytoma dNA was also performed. The mutation profile of the KRAS, NRAS, BRAF genes was studied by Sanger sequencing in tumor samples of various localizations.Results. The induction therapy (vCd (bortezomib + cyclophosphamide + dexamethasone), vRd (bortezomib + lenalidomide + dexamethasone), daratumumab therapy) was ineffective, death occurred 4 months after the first clinical manifestations appeared. Comparison of STR markers of circulating cell-free tumor dNA (cfdNA), Cd138+ bone marrow cells, and plasmacytoma revealed the largest number of involved loci exactly in plasmacytoma’ dNA. A mutation in the NRAS gene was found only in plasmacytoma’ dNA. This indicates the presence of another clone of tumor cells in the extra-medullary plasmacytoma. Molecular karyotyping of plasmacytoma using the arrayCGH method revealed rearrangements of many chromosomes. 1p32.3 bi-allelic deletion, amplification of 1q21, 8q24/MyC rearrangements and del17p13 were confirmed by arrayCGH molecular karyotyping and fISH studies in bone marrow and plasmacytoma.Conclusion. A comprehensive molecular genetic study of the extramedullary plasmacytoma’ substrate is necessary to understand the pathogenesis mechanisms and, on this basis, to develop differentiated therapeutic approaches.

Aim.To assess the safety and efficacy of autologous haematopoietic stem cell transplantation (auto-HSCT) in multiple myeloma (MM) patients with dialysis-dependent renal failure. Materials and methods.During a period from May 2010 to December 2016 fourteen MM patients with dialysis-dependent renal failure aged 48 to 65 years underwent auto-HSCT. After the induction therapy complete response, very good partial response, partial response were documented in 64, 29, 7% of patients, respectively. In no case was a renal response achieved. Haematopoietic stem cell mobilization in most patients (13/14) was performed according to the scheme: G-CSF 10 g/kg. Melphalan in 3 dosages was used as pre-transplant conditioning: 100, 140 and 200 mg/m2; 13 patients underwent a single and in one case underwent a tandem auto-HSCT against the background of hemodialysis. Evaluation of the antitumor and renal response was assessed on the 100th day after auto-HSCT. Subsequently, against the background of programmed hemodialysis and in the setting of high-dosed melphalan (100200 mg/m2), 13 patients underwent a single and one patient underwent a tandem auto-HSCT. At +100 days after auto-HSCT, an antitumor response and renal response were assessed. Results.The period of agranulocytosis after auto-HSCT was from 5 to 12 days (median 8,5) and was accompanied by infectious complications, cardiac and neurological dysfunctions. At +100 days after auto-HSCT, the complete response was confirmed in 71% patients and very good partial response was confirmed in 29% patients. The minimal renal response was registered in 2 patients (14%), hemodialysis was stopped. The transplant-related mortality was absent. After a median follow-up of 53 months 5-year progression-free survival was 59%, and overall survival was 93%. Conclusion.Carrying out auto-HSCT in patients with dialysis-dependent renal failure contributed to the achievement of a minimal renal response in 14% of cases, which allowed these patients to stop hemodialysis. Patients whose conditioning regimen was performed using melphalan at a dose of 200 mg/m2showed more frequent complications in the early post-transplant period compared to patients who received a lower dose of melphalan (100140 mg/m2). Auto-HSCT in MM patients with dialysis-dependent renal failure is a feasible and effective treatment method, which in some cases contributes to independence from hemodialysis.

Multiple myeloma (MM) is a disease characterized by spatiotemporal heterogeneity of tumor clones. Different genetic aberrations can be observed simultaneously in tumor cells from different loci, and as the disease progresses, new subclones may appear. The role of liquid biopsy, which is based on the analysis of tumor DNA circulating in the blood plasma, continues to be explored in MM. Here, we present an analysis of the STR profiles and mutation status of the KRAS, NRAS, and BRAF genes, evaluated in plasma free circulating tumor DNA (ctDNA), CD138+ bone marrow cells, and plasmacytomas. The prospective single-center study included 97 patients, with a median age of 55 years. Of these, 94 had newly diagnosed symptomatic MM, and three had primary plasma cell leukemia. It should be noted that if mutations were detected only in ctDNA, “non-classical” codons were more often affected. A variety of adverse laboratory and clinical factors have been associated with the detection of rare KRAS or NRAS gene mutations in bone marrow or ctDNA, suggesting that these mutations may be factors of an unfavorable prognosis for MM. Liquid biopsy studies provide undeniable fundamental information about tumor heterogeneity and clonal evolution in MM. Moreover, we focus on using liquid biopsy to identify new high-risk factors for MM.

Objective of the study: analysis of AL-amyloidosis (AL-A) diagnostics in real clinical practice and to determine the main approaches for the earlier detection of this disease.Materials and methods. A retrospective analysis of medical records of 34 patients with newly diagnosed AL-A.Results. The median time from first symptoms appearance to the diagnosis was more than 2 years. Most often, the pathological process in AL-A involves the kidneys, heart and gastrointestinal tract; moreover, at the time of diagnosis, most patients already have an injury of 2 or more organs. In half of the patients, a biopsy of the damaging organ was performed to verify the diagnosis; according to our data, histological examination of “easily accessible” locus not less informative. Symptoms characteristic of amyloidosis, such as periorbital purpura or macroglossia, are observed in a small part of patients and refer to late manifestations of the disease.Conclusion. The versatility of AL-A manifestations leads to a late diagnosis, which affects overall survival. The main signs were highlighted that should alert doctors in relation to this pathology.

Aim. To study immunohistochemical parameters of tumor plasma cells in bone marrow and to assess how the expression of adhesion molecule CD56 impacts overall survival (OS) of multiple myeloma (MM) patients. Materials & Methods. The trial included 35 patients (19 men and 16 women) aged 23 to 73 years (with median age of 58 years) with newly diagnosed MM. At disease onset plasmacytoma was diagnosed in 21 patients. In all patients bone marrow core biopsy was performed followed by histologic and immunohistochemical (IHC) examinations. IHC examination was based on the panel of CD56, CD166, CXCR4, Ki-67, and c-MYC/CD138 antibodies. Kaplan-Meier survival curves and significance assessment by means of Cox’s F-Test were used. Results. Expression mean values of most of studied markers (CD56, CXCR4, c-MYC, and Ki-67) in bone marrow of patients without plasmacytoma (n = 14) appeared to be higher than in patients with plasmacytoma at MM onset. Expression mean value is understood as percentage ratio of plasma cells expressing a studied marker to total cell count of tumor substrate. High expression of chemokine receptors (CXCR4), and adhesion molecules (CD56) probably inhibits plasma cell migration and impedes extramedullary tumor progression. Comparison of protein expression by tumor plasma cells in bone marrow in the groups with bone extramedullary plasmacytoma shows a distinct regularity referring to CD56 adhesion molecule. For example, CD56 expression is significantly (p < 0.05) lower in terms of the count of tumor plasma cells with marker expression in bone marrow of MM patients with extramedullary plasmacytoma compared with patients with bone plasmacytoma (1 ± 1 % vs. 65.71 ± 12.12 %). Comparison of MM patients’ OS depending on CD56 expression by tumor plasma cells in bone marrow showed that 4-year OS of patients with CD56 expression in bone marrow was significantly higher being 80 % vs. 38 % in the group with CD56 expression less than in 10 % of tumor cells. Conclusion. Expression of adhesion molecule CD56 in tumor plasma cells in bone marrow can be regarded as a prognostic factor in MM. Probably, when at disease onset CD56 expression is identified in less than 10 % of tumor cells in bone marrow, more detailed additional examination of patients should be carried out to rule out extramedullary lesions in different organs and tissues.