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Aim: to determine molecular diagnostics routine for different tissue samples in angioimmunoblastic T-cell lymphoma. Materials and methods. Molecular studies were performed for 84 primary AITL patients. The median age was 61 year (29-81); the male to female ratio was 48/36. T-cell and B-cell clonality was assessed by GeneScan analysis of rearranged T-cell receptor (TCRG, TCRB) and immunoglobulin heavy chain genes. For the quantitative determination of cells with RHOA G17V mutation real - time polymerase chain reaction (PCR) with allele - specific LNA modified primers was used. Results. In lymph nodes rearrangements of T-cell receptor genes were determined in 76 (90.5%) of 84 patients and were absent in 8 (9.5%) cases. Identification of the same clonal products of the TCRG and TCRB genes in the lymph node and in peripheral blood and/or bone marrow indicated the prevalence of the tumor process and was observed in 64.7% of patients. Clonal products in peripheral blood and/or bone marrow different from those in the lymph node indicated reactive cytotoxic lymphocyte population and were noted in 58.8% of AITL cases. Simultaneous detection of T- and B-cell clonality in the lymph node was observed in 20 (24.7%) of 81 patients. Cells with RHOA G17V mutation were detected in lymph node in 45 (54.9%) of 82 patients. The use of allele - specific PCR with LNA modified primers revealed presence of the tumor cells in peripheral blood in 100% and in bone marrow in 93.9% of patients with G17V RHOA mutation in the lymph nodes. Conclusion. The validity of different molecular assays performed on certain tissue samples for the diagnosis of angioimmunoblastic T-cell lymphoma has been evaluated. Quantitative allele - specific PCR assay for RHOA G17V mutation based on LNA modified primers possesses sufficient sensitivity for tumor process prevalence evaluation and minimal residual disease monitoring.

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. The study of genetic predictors of non-Hodgkin’s lymphomas prognosis is one of the most relevant areas of oncohematology. It is extremely interesting to search for integral markers that reflect the most important stages of tumor pathogenesis. DNA repair system plays one of the key roles in genomic instability. Aberrations of microsatellite repeats such as microsatellite instability (MSI), in particular elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) is characteristic for mismatch repair system and loss of heterozygosity (LOH) is an integral feature of genomic instability.Objective. Analysis of MSI, EMAST, LOH significance in follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and high-grade B-cell lymphoma (HGBL) patients.Materials and methods. The study was performed by multiplex PCR and fragment analysis with diagnostic panels COrDIS Plus and COrDIS MSI in 85 FL patients, 32 DLBCL patients, and 37 HGBL patients.Results. The frequency of LOH in the general FL group was 40/81 (49.4 %), MSI – 10/82 (12.2 %), EMAST – 15/81 (18.5 %). The frequency of LOH in the HGBL group was 21/31 (67.8 %), MSI – 11/37 (29.7 %), EMAST – 13/31 (41.9 %). The frequency of LOH in the DLBCL group was 18/29 (62.0 %), MSI – 5/32 (15.6 %), EMAST – 14/32 (43.8 %). When considering the morphological types of FL, it was noted that a higher frequency of genetic aberrations was characteristic of lymphomas with a more aggressive morphology (p

Background. Genetic instability, an important phenomenon involved in oncogenic transformation and tumor progression, is associated with the insufficiency of the multicomponent DNA repair complex, in particular, the nucleotide mismatch repair (MMR) system. The MMR defect manifests itself as abnormalities in DNA microsatellite repeats, or microsatellite instability (MSI). In the studies of colorectal cancer, the role of MSI in prognostication of the disease, and defining the choice of specific therapy with immune checkpoint inhibitors has been proven.However, in lymphatic system tumors, the significance of this phenomenon is poorly understood. Determination of genetic instability in the onset of follicular lymphoma, a disease characterized by a heterogeneous course, may have prognostic value.Objective: to determine the genetic instability at the onset of follicular lymphoma.Materials and methods. Here we report an analysis of 24 microsatellite repeats and amelogenin loci in tumor cells of 46 follicular lymphoma patients.Results. In the studied cohort, lesions in microsatellite repeats were presented by MSI in 9 cases (19.6 %) and the loss of heterozygosity (LOH) in 19 cases (41.3 %). Most frequent lesions were found for the SE33 marker located at the q14 locus of chromosome 6. A significant association was shown between MSI and the double-hit follicular lymphoma group with rearrangements of the MYC and BCL2/BCL6 genes.Conclusion. Thus, our data indicate that the MSI phenomenon might be involved in the pathogenesis of the lymphatic tumors and particularly follicular lymphoma. However further studies on the expanded cohorts of patients are required to define the possible prognostic value of MSI in lymphatic tumors.

Introduction. Аngioimmunoblastic T-cell lymphoma (AITL) is a T-cell lymphoma, characterized by abundant polymorphocellular infiltrate of lymph nodes with the small number of tumor CD4+ T-cells. AITL could often be misdiagnosed as reactive processes and other lymphomas, including Hodgkin’s lymphoma. Molecular methods of determining clonality are used to confirm the diagnosis. TCR gene rearrangements detected in the lymph nodes may not coincide with those detected in the bone marrow (BM), blood or skin, that makes their interpretation difficult. Recently discovered point somatic RHOA (Ras homolog gene family, member A) Gly17Val mutation is present in 53–71 % of angioimmunoblastic T-cell lymphomas.The aim of the study was to evaluate the number of RHOA Gly17Val mutated cells in different tissues of AITL patients and to correlate it with corresponding T-cell clonality results.Materials and methods. TCRG and TCRB gene rearrangements were PCR-amplified according to BIOMED-2 standardized protocol and analyzed by capillary electrophoresis on ABI Prism 3130. Gly17Val mutation was analyzed by quantitative allele-specific (qAS) TaqMan Real-Time PCR assay. Lymph nodes (LN) and skin biopsies, blood and BM samples were studied for 40 patients with AITL.Results. The clonal TCR gene rearrangements were found in 37 (92 %) of 40 patients in LN and in 26 (96 %) of 28 patients in BM, but they were not matched in length in LN and BM in 12 (46 %) of 26 patients. RHOA (Gly17Val) mutation in LN was revealed in 60 % (24 of 40) patients. Number of cells with RHOA mutation was highest in the LN (in average 26.7 % of the total cells), while in the BM RHOA mutation were undetectable (in 7 patients), or detected in 10 patients in a low quantity (in average 2 % of the total cells). Skin, blood and BM samples with the T-cell clonality peaks that differ from those found in the LN were also negative for the presence of cells having RHOA Gly17Val mutation. Also, in four patients we showed that clonal products in BM and blood that do not coincide with LN refer to CD8+ lymphocytes.Conclusions. The results of the study demonstrate that the quantitative determination of cells with the mutation of RHOA Gly17Val must be taken into account in staging the disease and interpreting the results of T-cell clonality assay. Clonal cells with rearrangements not matching those identified for the LN should be considered reactive.

Material platforms based on interaction between organic and inorganic phases offer enormous potential to develop materials that can recreate the structural and functional properties of biological systems. However, the capability of organic-mediated mineralizing strategies to guide mineralization with spatial control remains a major limitation. Here, we report on the integration of a protein-based mineralizing matrix with surface topographies to grow spatially guided mineralized structures. We reveal how well-defined geometrical spaces defined within the organic matrix by the surface topographies can trigger subtle changes in single nanocrystal co-alignment, which are then translated to drastic changes in mineralization at the microscale and macroscale. Furthermore, through systematic modifications of the surface topographies, we demonstrate the possibility of selectively guiding the growth of hierarchically mineralized structures. We foresee that the capacity to direct the anisotropic growth of such structures would have important implications in the design of biomineralizing synthetic materials to repair or regenerate hard tissues., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Author(s).)