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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.

Background. 6-mercaptopurine (6-MP) is a drug that is included in the treatment protocols for children and adults with acute lymphoblastic leukemias/lymphomas (ALL/LBL). It is known that individual differences in 6-MP tolerance can be explained by the TPMT and NUDT15 polymorphisms.Aim. To determine 6-MP toxicity profile in adult patients with Ph-negative ALL/LBL treated by ALL-2016 protocol, depending on the TPMT and NUDT15 polymorphisms.Materials and methods. The study included 54 adult patients with Ph-negative ALL/LBL (40 male and 14 female). The median age was 31 (18-51) years. T-ALL/LBL was diagnosed in 29 patients, B-ALL/LBL - in 22, acute leukemia with a mixed immunophenotype - in 3. All patients received treatment according to the multicenter study ALL-2016 (ClinicalTrials.gov, NCT03462095). polymorphisms in NUDT15 (*2, *3) and TPMT (*2, *3A, *3B, *3C) genes were detected using the allele-specific real-time polymerase chain reaction. Genomic DNA was extracted from patients peripheral blood samples. On the induction and consolidation therapy by the protocol, the received and proper 6-MP doses were calculated for all the patients. Drug toxicity was evaluated based on clinical and laboratory data.Results. TPMT and NUDT15 polymorphisms were detected in 11 (20 %) patients, more often in B-ALL - 7 (32 %) of 22 (p TPMT, NUDT15 polymorphisms only at consolidation IV (p = 0.01). we didn't find a correlation between the 6-MP toxicity and the polymorphisms in our patients (p >0.05).Conclusion. There were no differences in the received dose of 6-MP and the incidence of toxicity in adult patients between Ph-negative ALL/LBL with or without TPMT and NUDT15 polymorphisms treated according to ALL-2016 protocol (p >0.05). further studies including evaluation of 6-MP metabolites concentrations are required for a more complete understanding of the metabolism of this drug.

In chronic lymphocytic leukemia, the risk of second tumors including hematological malignancies, with which the use of purine nucleosides and alkylating agents in treatment of chronic lymphocytic leukemia is most often associated, is significantly increased. Concurrent detection of this disease and various hematological tumors is a rare occurrence in hematological practice. Use of cytogenetic method or analysis allows to differentiate between 2 tumors and confirm differences in genetic abnormalities in different clones and on different levels of cell differentiation. This article presents a clinical case of simultaneous chronic lymphocytic leukemia and myelodysplastic syndrome with 2 clones with different cytogenetic abnormalities: partial trisomy of chromosome 12 and deletion of the long arm of chromosome 5 formed at different levels of cell differentiation.

Background . Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal diseases of the hematopoiesis system characterized by dismyelopoiesis and cytopenia, the presence of cytogenetic aberrations and a high risk of transformation into acute myeloid leukemias. Diagnosis of MDS requires a comprehensive approach and mandatory performance of cytological, cytochemical and cytogenetic studies of bone marrow aspirate, as well as histological examination of trephine biopsy. However, in some cases it is necessary to undergo a diagnostic test that would allow verification of the MDS. The study of bone marrow aspirate by multicolor flow cytometry (MFC) can be considered as an additional diagnostic criterion in the diagnosis of MDS.The objective of the study was to estimate the incidence of myelodysplastic features in patients with various forms of MDS by the MFC method. Materials and methods . The study included 79 patients with MDS: 8 with MDS with 5q deletion, 33 with MDS without excess blast cells and 38 with excess of blasts. A bone marrow aspirate test was performed by 6-color flow cytometry. The control group included 35 donors of allogeneic bone marrow. The analysis resulted in a conclusion on the Ogata score scale, the Wells prognostic scale and the combined Ogata–Wells scale. When using the screening method, the presence of two or more cytometric signs of MDS was detected in 60 (75.9 %) of 79 MDS patients. Wells score was higher in MDS group with an excess of blast than in others. Using the combined Ogata–Wells scale, cytometric aberrations were found in 70 (88.6 %) of 79 MDS patients. In patients with MDS with an excess of blasts, the incidence of increased CD34+ and/or CD117+ myeloid cells was higher than in MDS patients without an excess of blasts and an MDS with a 5q deletion. The frequency of abnormal cytometric parameters (anomalous expression of CD34, CD117, CD56+ myeloblasts) in these groups did not differ. In patients with isolated 5q deletion and MDS without excess of blasts, an increased proportion of CD7+CD34+ cells was more often detected than in MDS with an excess of blasts.Conclusion . Thus, cytometric abnormalities in MDS are common, even in patients without excess of blasts. The MFC method can be used as an additional diagnostic method in the initial diagnosis of MDS.