Overview of histiocytic and dendritic disorders by the 5th version of WHO Classifi cation of Hematolymphoid Tumours from 2022.

BACKGROUND: Histiocytoses are rare disorders characterized by the accumulation of macrophages, dendritic cells, or monocyte-derived cells in various tissues and organs of children and adults, with a wide range of clinical manifestations, presentations, and histology. The histiocytoses are classified according to the WHO Classification, the last version of which was published in 2022, or according to the Histiocyte Society Classification, with the last version published in 2016. PURPOSE: This text provides an overview of histiocytoses as described in the WHO Classification 2022.

Monoclonal gammopathy of clinical signifi cance with osteosclerotic lesions - a case report and a literature review.

INTRODUCTION: Multiple myeloma is a common plasma cell neoplasia usually accompanied by the formation of osteolytic foci, whereas osteosclerotic myeloma is a very rare form of plasma cell dyscrasia. When osteosclerotic myeloma is detected, osteosclerotic foci are usually part of the POEMS syndrome. Osteosclerotic myeloma without other manifestations of the POEMS syndrome is an unusual finding. CASE DESCRIPTION: In a 46-year-old woman, osteosclerotic changes of the temporoparietal region caused soft tissue induration over this lesion, which initiated further investigation. Imaging studies subsequently showed multiple osteosclerotic foci in the skull. Examination of blood proteins revealed 8 g/L of IgG-lambda monoclonal immunoglobulin, subclass IgG1. In search of the cause of the osteosclerotic changes, FDG-PET/CT was performed, which revealed no FDG accumulation, i.e., no other tumor (breast or stomach cancer). Low-dose CT showed irregular bone structure, but not significant osteolytic or osteosclerotic foci. To map the extent of osteosclerotic changes, NaF-PET/CT imagination followed, which revealed multiple spots with high fluoride accumulation. A parietal bone biopsy showed osteosclerosis with minor clonal plasma cell infiltration. Trepanobioptic bone marrow sampling revealed an infiltration of bone marrow with atypical plasma cells in 8%. Flow-cytometric examination of bone marrow showed 0,37% of plasma cells, however predominantly (91%) clonal with lambda expression. MRI of the brain identified asymptomatic meningeal thickening. There was no evidence of POEMS syndrome in the patient; thus, we concluded the diagnosis as monoclonal gammopathy of clinical significance with osteosclerosis which was previously termed osteosclerotic multiple myeloma. CONCLUSION: Monoclonal gammopathy of clinical significance (MGCS) with osteosclerotic skeletal changes, documented on CT and multiple foci with intensive osteoneogenesis, documented on NaF-PET/CT without evidence of POEMS syndrome, is an extremely rare form of plasma cell dyscrasia. This publication documents the unique clinical manifestations of IgG-lambda type plasma cell proliferation without signs of POEMS syndrome and the role of NaF-PET/CT imaging. Classification of this disease as MGSC with osteosclerotic manifestations is more consistent with the indolent nature of the disease with a significantly better prognosis, compared with multiple myeloma.

Waldenström's macroglobulinemia - clinical symptoms and review of therapy yesterday, today and tomorrow.

BACKGROUND: Waldenström macroglobulinemia (WM) is a lymphoplasmocytic lymphoma with immunoglobulin M monoclonal protein. The incidence of this disease is very low (0.4/100,000), so that this disease can be regarded as an orphan's disease. It means that new drugs are often tested and registered for more frequent diseases. PURPOSE: In this review we will focus on the efficacy of the new drugs for WM. RESULTS: The current treatment options for symptomatic WM patients include alkylating agent cyclophosphamide and anti-CD20 monoclonal antibodies. Therapy with rituximab and bendamustin resulted in longer therapeutic response then therapy with rituximab, cyclophosphamide and dexamethasone. Many drugs, used in multiple myeloma (MM), shoved promising results in WM patients. Bortezomib is effective in WM, but its neurotoxicity is higher in WM than in MM patients. Therefore, new proteasome inhibitors, carfilzomib and ixazomib, are better tolerated as documented in several studies. New types of antiCD20 antibody (obinutuzumab) can be used in patients with rituximab intolerance. in five of our patients with WM, obinutuzumab and bendamustin reached deeper responses than therapies administered in previous lines of therapy. Oral Bruton tyrosine kinase (BTK) inhibitor ibrutinib alone and in combination with rituximab have extended the treatment options for WM patients. New BTK inhibitors (e. g. acalabrutinib, zanubrutinib, and vecabrutinib) were tested and their lower toxicity (atrial fibrillation) was documented. Moreover, the BCL2 inhibitor venetoclax is newly tested. CONCLUSION: New antiCD20 antibody (obinutuzumab) is of advantage in patients with WM with rituximab intolerance as well as bendamustin and new proteasome inhibitors (ixazomib and carfilzomib) or new BTK inhibitors with lower cardiotoxicity. Many of the abovementioned drugs do not have official registration for WM and can be administrated with the consent of the health care provider only. Thus, this work brings evidence of their efficacy.

Therapy of Castleman's disease with siltuximab - case report and review of literature.

BACKGROUND: Idiopathic multicentric Castleman disease (iMCD) is characterized by constitutional symptoms, enlarged lymph nodes and laboratory test abnormalities, which are primarily related to the overproduction of interleukin-6 (IL-6). This form (iMCD) was treated earlier with cytostatics used for lymphoma, later with bio-logic therapy as rituximab, immunodulatory drugs and proteasome inhibitors, and in the last years with an anti-IL-6 antibody, siltuximab. Siltuximab is a human-mouse chimeric immunoglobulin G1k monoclonal antibody against human IL-6 approved in the European Union for the treatment of iMCD. In view of the limited treatment options for iMCD, this case report aimed to evaluate the efficacy and safety of siltuximab in the management of this condition. CASE: We describe a young woman with iMCD diagnosed at the age of 25 years. For first line treatment, rituximab and dexamethasone were used without any cytostatic because the patient wished to give birth to a healthy child in the future. However, the response after this first line therapy was short. In addition, after 3 years from the start of rituximab + dexamethasone therapy, it was necessary to administer treatment for the relapse of iMCD. We decided for siltuximab in this young woman, still aged < 30 years, and started administration of siltuximab in 3-week intervals. RESULTS: After administration of first two infusions of siltuximab, all inflammatory markers returned to normal value. Moreover, serum hemoglobin and albumin levels as well as C-reactive protein normalized after the first two administrations of siltuximab. The clinical response continue, siltuximab is still administered in 3-week intervals. PET/CT with fluorodeoxyglucose confirmed a very good anatomic and metabolic response to the treatment. Siltuximab demonstrated a favorable safety profile, and the prolonged treatment was well tolerated. CONCLUSION: This result is encouraging and demonstrates the potential of siltuximab as treatment of CD. As earlier published, this case confirms that significantly elevated inflammatory markers in a patient with CD predict a good response to siltuximab.

Patients benefi ts from physicians empathy and results of including of empathy development into medical training.

BACKGROUND:  The extent of empathy is an individual human property, not completely dependent on cognitive intelligence. People arise with certain genetic fundament for empathy but the ability to perceive empathically develops further during the life. There has been much discussion in the medical literature about the importance of empathy and physician communication style in medical practice. Empathy has been shown to have a very real positive eff ect on patients outcomes. The literature suggests that empathy training is warranted and should be incorporated into surgical residencies through didactics, role-playing and simulations, and apprenticeship to empathic attending role models. PURPOSE: This paper reviews empathy and its importance as it pertains to the physician-patient relationship and improving patients outcomes, and the need for increased education in empathy during medical training.

Retroperitoneal fibrosis - diagnosis and treatment.

Idiopathic retroperitoneal fibrosis (IRF) is a rare condition characterized by the development of a peri-aortic and peri-iliac tissue showing chronic inflammatory infiltrates and pronounced fibrosis. Ureteral entrapment with consequent obstructive uropathy is one of the most common complications which can lead to acute renal failure and, in the long term, to varying degrees of chronic kidney disease. Common symptoms at onset include lower back, abdominal or flank pain. Pain is frequently referred to the hip, to the groin and to the lateral regions of the leg, often with nocturnal exacerbations and not responding to position changes. The disease is commonly associated with signs of systemic inflammatory response (malaise, fever, and anorexia and weight loss). Glucocorticoids are considered the cornerstone of the therapy. The use of other immunosuppressive agents, including cyclophosphamide, azathioprine, methotrexate, mycophenolate mofetil and biological agents such as rituximab, tocilizumab and infliximab have been reported as a valuable option mostly in case reports, cases series and small studies. These agents allowed to reduce cumulative dose of glucocorticoids and their adverse effects. Combined therapy is preferable for all patients who suffer from significant glucocorticoid- related toxicity or in cases where glucocorticoids alone are insufficient to treat the condition.

Rosai-Dorfman-Destombes disease - histiocytic disorder with inflammatory manifestation.

BACKGROUND: Rosai-Dorfman-Destombes disease (RDD) is a rare histiocytosis characterized by accumulation of activated histiocytes within affected tissues. Although the immunophenotype of this disease was described, the pathophysiology of this disease is still not sufficiently understood. Recent studies have found NRAS, KRAS, MAP2K1, and ARAF mutations in RDD lesions, raising the possibility of a clonal origin in some forms of RDD while in other cases reactive origin or association with other malignant and autoimmune disease is supposed. RDD is a widely heterogeneous entity with a range of clinical phenotypes occurring in some patients in association with autoimmune or malignant diseases. Its therapy should reflect the localization of the disease. Monotherapy with glucocorticoids is sufficient only in limited disease. In patients with advanced disease, combined nodal and extranodal forms of RDD need more intensive therapy. In older publications, antimetabolites, vinca alkaloids and prednisone were used; in recent publications, remissions after cladribine, rituximab, sirolimus, thalidomide, lenalidomide and cobimetinib were described. PURPOSE: This text summarizes current knowledge about this rare disease and reviews the therapeutic options.

Slow increase of bilirubin concentration during administration of lenalidomide, bortezomib and dexamethasone for multiple myeloma (unmasking previously undiagnosed Gilbert syndrome) and disappearance of necrobiotic xanthogranuloma after complete remission of multiple myeloma.

BACKGROUND: Lenalidomid ranks among immunomodulatory drugs. There are a few of the more common side effects, like a higher risk of venous trombembolism or diarrhea. Other side effects are rare. The hyperbilirubinemia described in this article can be assigned to them. In our case, the increase of bilirubin was associated with unrecognized Gilbert syndrome. CASE DESCRIPTION: We report a patient with multiple myeloma and necrobio-tic xanthogranuloma (NXG) of the skin and liver. After the treatment with bortezomib, lenalidomid and dexamethasone, complete remission was attained after 4 cycles with decrease of monoclonal immunoglobulin to an unmeasurable concentration. At the same time, the dis-appearance of cutaneous and hepatic lesions of NXG on FDG-PET/CT was evident. The administration of bortezomib was stopped after 8 cycles and only continued with lenalidomide as a maintenance therapy. However, after four cycles of this therapy, bilirubin increased above the upper limit and the increase continued till the 11th month of lenadomide administration, when bilirubin reached the highest concentration of 75 μmol/l (more than the three-fold of the upper limit, grade III toxicity). The patient had asymptomatic hyperbilirubinemia with no underlying liver disease or renal impairment while being on lenalidomide therapy. Genetic studies proved mutation; insertion in the promotor gene UGT1A1 typical for Gilbert syndrome. Hyperbilirubinemia may be attributed to the unmasking of previously undia-gnosed Gilbert syndrome. Therefore, the therapy with lenalidomide was interrupted after 11 months. The bilirubin level decreased after the discontinuation of the drug. CONCLUSION: NXG disappeared after fulfilling complete remission of multiple myeloma with disappearance of monoclonal immunoglobulin. This observation supports the hypothesis that monoclonal immunoglobulin has a crucial role in the ethiopathogenesis of NXG and suggests the treatment of monoclonal gammopathy if present in a patient with NXG, hoping that this will result in xantogranuloma disappearance.

Diagnostic relevance of 18F-FDG PET/CT in newly diagnosed patients with monoclonal gammopathy of undetermined significance (MGUS): Single-center experience.

Monoclonal gammopathy of undetermined significance (MGUS) is a known precursor of more serious cancers, such as multiple myeloma (MM), Waldenström macroglobulinemia (MW) and other lymphoproliferative disorders. Using 18F-FDG PET/CT, we aimed to evaluate its benefit in early detection of various accompanying disorders and illnesses in MGUS patients. We prospectively analyzed the diagnostic relevance of 18F-FDG PET/CT in 390 newly diagnosed MGUS patients. On 18F-FDG PET/CT scans, the presence of focal or diffuse areas of detectable increased tracer uptake was recorded in 37 (9.5%) MGUS patients. The most frequent pathology was lymphadenopathy (3.8%), followed by thyroid diseases (2.1%), rheumatic diseases (1.8%), and other solid malignancies (1.5%). These results have major implications for confirmed associations of MGUS with numerous malignant and non-malignant disorders. We believe that 18F-FDG PET/CT imaging in newly diagnosed MGUS patients may be useful in early detection of other serious pathologies, not only in predicting progression of MGUS to active MM, and should be strongly recommended if available.

Bortezomib retreatment is effective in relapsed multiple myeloma patients - real-life clinical practice data.

Nowadays, bortezomib, a proteasome inhibitor, is widely used in treatment of newly diagnosed or relapsed multiple myeloma. The aim of this study was to analyze efficiency of bortezomib retreatment in patients with relapsed or refractory multiple myeloma. From 2004 to 2016, 283 patients were retrospectively evaluated at all hematological centers in the Czech Republic. Bortezomib was administered at the standard dosing and in combined therapy with corticosteroids, chemotherapy or thalidomide. Before bortezomib retreatment, 61% of patients received previous lenalidomide treatment, 40.6% autologous transplantation, and median number of prior lines of therapy was three. In total, 21% of patients were refractory to the first bortezomib treatment. In bortezomib retreatment, overall response rate was 34.5%, median progression-free survival was 7.8 months (95% CI: 6.7-8.9), median duration of response was 10.5 months (95% CI: 8.0-13.0) and median overall survival was 20.3 months (95% CI: 17.9-22.7). Grade 3-4 adverse events included thrombocytopenia, neutropenia, anemia and infection. Neuropathy grade 2 or higher occurred in 19.4% of patients. We conclude that bortezomib retreatment is an effective and safe therapeutic alternative for relapsed or refractory multiple myeloma patients.

Methodology and results of real-world cost-effectiveness of carfilzomib in combination with lenalidomide and dexamethasone in relapsed multiple myeloma using registry data.

OBJECTIVE: To predict the real-world (RW) cost-effectiveness of carfilzomib in combination with lenalidomide and dexamethasone (KRd) versus lenalidomide and dexamethasone (Rd) in relapsed multiple myeloma (MM) patients after one to three prior therapies. METHODS: A partitioned survival model that included three health states (progression-free, progressed disease and death) was built. Progression-free survival (PFS), overall survival (OS) and time to discontinuation (TTD) data for the Rd arm were derived using the Registry of Monoclonal Gammopathies in the Czech Republic; the relative treatment effects of KRd versus Rd were estimated from the phase 3, randomised, ASPIRE trial, and were used to predict PFS, OS and TTD for KRd. The model was developed from the payer perspective and included drug costs, administration costs, monitoring costs, palliative care costs and adverse-event related costs collected from Czech sources. RESULTS: The base case incremental cost effectiveness ratio for KRd compared with Rd was €73,156 per quality-adjusted life year (QALY) gained. Patients on KRd incurred costs of €117,534 over their lifetime compared with €53,165 for patients on Rd. The QALYs gained were 2.63 and 1.75 for patients on KRd and Rd, respectively. CONCLUSIONS: Combining the strengths of randomised controlled trials and observational databases in cost-effectiveness models can generate policy-relevant results to allow well-informed decision-making. The current model showed that KRd is likely to be cost-effective versus Rd in the RW and, therefore, the reimbursement of KRd represents an efficient allocation of resources within the healthcare system.

Bortezomib and Thalidomide Treatment Results in Newly Diagnosed Transplant-Ineligible Multiple Myeloma Patients are Comparable in Long-Term Follow-Up.

BACKGROUND: Thalidomide-and bortezomib-containing regimens are widely used for transplant-ineligible newly diagnosed multiple myeloma patients. The aim of this study was to analyse the efficiency of thalidomide-or bortezomib-based regimens in long-term follow-up. MATERIALS AND METHODS: From 2008 to 2012, 142 transplant-ineligible newly diagnosed multiple myeloma patients were analysed retrospectively. Bortezomib was administered at the standard dosing of 1.3mg/m2 weekly, and thalidomide was administered at a daily dose of 100mg. Both drugs were combined with cyclophosphamide and dexamethasone. A total of 95 patients were treated with thalidomide and 47 with bortezomib. A median four cycles of treatment were administered in both groups. RESULTS: In the thalidomide group, the overall response rate was 60.6%, the median progression-free survival (PFS) was 10.3 months (95% CI 7.4-13.2) and the median overall survival (OS) was 35.1 months (95% CI 23.9-46.3). In the bortezomib group, the overall response rate was 51.1%, the median PFS was 11.9 months (95% CI 8.8-15) and the median OS was 25.4 months (95% CI 9.3-41.6). There was a statistically significant difference in OS (p = 0.027), favouring the cyclophosphamide/thalidomide/dexamethasone group, but the response rates and PFS intervals were not significantly different between both groups. The median follow-up in the thalidomide group was 35.1 months (95% CI 0.2-95.9) compared to 25.1 months (95% CI 0.4-60.6) in the bortezomib group (p = 0.004). The incidence of serious adverse events was comparable in both groups. CONCLUSION: In conclusion, the results of bortezomib treatment are comparable to thalidomide treatment under conditions of short administration. According to other clinical trials, long-term bortezomib treatment provides an additional advantage for PFS and OS.

Lenalidomide and dexamethasone in treatment of patients with relapsed and refractory multiple myeloma - analysis of data from the Czech Myeloma Group Registry of Monoclonal Gammopathies.

Lenalidomide (LEN) is an immunomodulator with clinical activity against myeloma cells. Based on the pivotal phase 3 trials MM-009 and MM010, the combination of lenalidomide and dexamethasone(DEX) was approved for patients with multiple myeloma who received at least one prior therapy. Here, we evaluated LEN/DEX therapy in unselected population and subsequently in selected sub-groups of patients with relapsed/refractory multiple myeloma followed in the Registry of Monoclonal Gammopathies of the Czech Myeloma Group. Altogether 858 patients were treated with LEN/DEX in the Czech Republic and Slovakia until end of 2017. The analyzed sub-groups were defined as patients with high risk cytogenetic aberrations and patients with relapsed and refractory MM. The overall response rate (ORR; partial remission or better response, PR) in the whole group of patients was 46.3% for all lines of therapy, 26.4% for high-risk group and 32.1% for relapsed and refractory group. Medians of overall survival (OS) in the same cohorts were as follows: 25.6, 15.7 and 18.5 months, progression free survival (PFS) was: 11.2, 6.4 and 9.0 months respectively. The most common adverse events were hematologic and infectious. In conclusion we found that our results correlated with those found in other studies in terms of response rates, survival measures, and also of treatment toxicity.

Epidemiology of Plasma Cell Leukemia in the Czech Republic.

BACKGROUND: Plasma cell leukemia (PCL) is a rare but most aggressive form of monoclonal gammopathies. PCL is characterized by the presence of clonal plasma cells in peripheral blood. There are two forms of PCL - primary which presents de novo in patients with no evidence of previous multiple myeloma and secondary which is a leukemic transformation of relapsed or refractory dis-ease in patients with previously recognized multiple myeloma. MATERIALS AND METHODS: This is the first study to provide information on PCL epidemiology in the Czech population us-ing The Czech National Cancer Registry (CNCR) as the basic source of data for the population-based evaluation of PCL epidemiology. RESULTS: Accord-ing to CNCR data, there were on average six newly dia-gnosed cases of PCL and four deaths caused by PCL each year in the Czech Republic in the period 2000- 2015. PCL incidence in the Czech Republic was reported at 0.57 per million in 2000- 2015. We suppose that most reported cases of PCL are primary PCL because secondary PCL is a relapse of a previously reported myeloma and, in most cases, is not coded as an independent dia-gnosis in the CNCR. CONCLUSION: Data from registries such as the CNCR can provide useful information on epidemiology of various dis-eases. These data, however, have several limitations, such as dia-gnostic criteria and proper cod-ing of not only the dis-ease itself, but also its various forms. These limitations have to be taken into account dur-ing the process of results interpretation. Key words plasma cell leukemia -  epidemiology -  Czech National Cancer Registry (CNCR) -  Czech Republic.

Plasma Cell Leukemia ­â€Š the Forgotten Dis­ease

BACKGROUND: Plasma cell leukemia (PCL) is a rare dis-ease and possibly the most aggressive form of monoclonal gammopathy. It is classified into two forms -  primary PCL that occurs without a previously identifiable multiple myeloma stage, and secondary PCL that develops from previously dia-gnosed multiple myeloma. These two forms have different cytogenetic and molecular profiles, but both forms have an aggressive clinical course. Combinations of different therapeutic approaches includ-ing autologous stem cell transplantation and currently proteasome inhibitors and immunomodulatory drugs are used to treat PCL. Current dia-gnostic criteria, developed in the 1970s, may underestimate PCL prevalence; thus, prospective re-evaluation is be-ing considered. PURPOSE: The aim of this study is to review all available information about PCL with an emphasis on dia-gnostics, treatment, and circulat-ing plasma cells features. CONCLUSION: Although PCL is rare, it is quite a severe dis-ease. Current treatments us-ing the latest therapeutics have prolonged patient survival. However, due to the low incidence of PCL, information about the dis-ease is very limited and comes mostly from small retrospective studies. Further studies of PCL are needed, because new information could increase in patient survival and our understand-ing of its pathogenesis. Key words plasma cell leukemia -  multiple myeloma -  plasma cells -  cytogenetics -  treatment This work was supported by grant NV18-03-00203. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submited: 2. 11. 2018 Accepted: 18. 11. 2018.

Simplified novel prognostic score for real-life older adults with multiple myeloma-registry-based analysis.

The main goal was to find a simple prognostic to evaluate overall survival of patients older than 65 years of age with myeloma. Retrospective registry-based analysis from the Registry of Monoclonal Gammopathies was conducted. Patients over 65 years with symptomatic myeloma were included. The four major parameters with impact on survival were identified: male gender, age > 75, creatinine > 152 µmol/L, and ECOG performance status 2-4. The patients were scored as good (0 points), intermediate good (1 point), intermediate poor (2 points), poor (3-4 points). Patients (1410 MM) were included. Median OS (months) was 65.7 (95% CI 49.8-81.7) for good, 51.0 (44.1-57.8) for intermediate good, 32.2 (26.2-38.2) for intermediate poor, and 18.9 (15.1-22.7) for poor. The differences in OS were statistically significant (p < 0.0001). Good score was used as reference for hazard ratios, which for each other score were 1.43 (1.09-1.84) for intermediate good, 2.58 (2.00-3.33) for intermediate poor, and 3.88 (2.94-5.10) for poor. Time to progression showed medians (months) 20.5 (17.4-62.4) for good, 19.3 (17.0-21.7) for intermediate good, 19.6 (16.2-23.0) for intermediate poor, and 13.0 (10.8-15.2) for poor. The suggested scoring system provides readily available information about the prognosis of MM patients above 65 years.

Retreatment with lenalidomide is an effective option in heavily pretreated refractory multiple myeloma patients.

The combination of lenalidomide and dexamethasone is the current gold standard for treatment of relapsed multiple myeloma. This study analyzes the efficiency of repeated lenalidomide treatment in patients with relapsed and refractory multiple myeloma. A total of 41 patients were prospectively evaluated at the University Hospital Brno. Lenalidomide was administered at standard dosing and in combination with corticosteroids and/or chemotherapy. The maximum cumulative dose of lenalidomide was limited to 4,200 mg because of Czech health insurance rules. Before the second lenalidomide treatment, all patients were refractory to the last treatment; previously, 95% of patients had bortezomib treatment, 48% had autologous transplantation and the median number of prior therapy lines was three. A partial 14.2% or better response was achieved with the second lenalidomide treatment. The median progression-free survival was 4.8 months, and median overall survival was 11.9 months. Unfortunately, predicting risk factors in lenalidomide retreatment proved unsuccessful. Although our treatment results were significantly affected by limited Czech health care system coverage for lenalidomide, we established that its repeated treatment is an effective therapeutic alternative for heavily pretreated patients with relapsed and refractory multiple myeloma.

[MicroRNA Analysis for Extramedullary Multiple Myeloma Relapse]. / Analýza mikroRNA u extramedulárního relapsu mnohocetného myelomu.

INTRODUCTION AND AIMS: Multiple myeloma (MM) is the second most common hematooncological disease. Patient survival has been greatly improved by the introduction of new drugs into clinical practice, but survival is negatively affected by the so-called extramedullary relapse (EM), caused by the loss of plasma cell dependence on the bone marrow microenvironment and their migration out of the bone marrow. The nature and causes of this process are currently unclear. MicroRNAs (miRNAs) are short, non-coding RNA molecules involved in many physiological and pathological processes. Their significance in the pathogenesis of MM has been demonstrated by several studies. We assume that they are also involved in the development of the EM. The aim of this study was to analyze different miRNA expression between MM and EM patients. MATERIAL AND METHODS: Using next generation sequencing, we analyzed 39 samples of bone marrow cells from MM patients at diagnosis and 9 bone marrow plasma samples of EM patients. RESULTS: In total, 2,278 miRNA were sequenced, but only 658 miRNAs were analyzed as they were expressed in all samples and had at least 20 reads. Expression data were generated using the Chimira tool from fastq data. All sequences were mapped using miRBase v20. Further analyses were performed using the R/Bioconductor package. The Bayesian procedure was used for normalization of expression. P values were adjusted using the Benjamini-Hochberg method. Analysis found 10 miRNA (p < 0.0005) that are statistically significantly expressed in EM vs. MM patients - these are miR-26a-5p, miR-26b-5p, miR-30e-5p, miR-424-3p, miR-503-5p, miR-767-5p, miR-105-5p, miR-5695-5p, miR-450b-5p and miR-92b-3p. These miRNAs will be further verified by qPCR method on a larger set of MM and EM patients. CONCLUSION: Our pilot study has shown that there are differentially expressed miRNAs between MM and EM patients.Key words: multiple myeloma - microRNA - carcinogenesis - next generation sequencing The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papersThis work was supported by grant MZ CR AZV 17- 29343A. Submitted: 17. 3. 2018Accepted: 20. 3. 2018.

Minimal Residual Disease Assessment in Multiple Myeloma by Multiparametric Flow Cytometry.

BACKGROUND: Progress in treatment of multiple myeloma extensively increased patient remission rates, so minimal residual disease (MRD) detection becomes essential to assess the effectivity of treatment and depth of complete response. Nowadays, multiparametric flow cytometry (MFC) is the most used method for monitoring of MRD presence in the bone marrow of multiple myeloma patients; however, detection on molecular level can be used as well. It is evident that choice of protocol used for MFC-MRD assessment can significantly affect required results; nevertheless, standardized and highly sensitive approach of "next generation flow" is already available. Although benefit of MRD assessment as an independent predictor of progression-free survival and overall survival is known, very recent research showed that MRD-negative status surpasses the prognostic value of complete response achievement for progression-free survival and overall survival. AIM: This review is focused on use MFC in MRD assessment in multiple myeloma. The technical aspects and clinical benefits of this approach are mentioned as well. CONCLUSION: The information about MRD level detected by highly sensitive and reproducible MFC can be potentially used as a biomarker to evaluate the efficacy of different treatment strategies, help on treatment decisions and act as a surrogate for overall survival in multiple myeloma patients.Key words: multiple myeloma - minimal residual disease - flow cytometry - plasma cells.

Whole Exome Sequencing of Aberrant Plasma Cells in a Patient with Multiple Myeloma Minimal Residual Disease.

Multiple myeloma is a plasma cell dyscrasia. It is the second most common hematological malignancy which is characterized by proliferation of clonal plasma cells producing harmful monoclonal immunoglobulin. Despite treatment modalities greatly evolved during the last decade, small amount of aberrant residual cells reside in patients after therapy and can cause relapse of the disease. Characterization of the residual, resistant clones can help to reveal important therapeutic targets for application of effective and precious treatment. We use CD38, CD45, CD56 and CD19 sorted aberrant plasma cells to perform next generation sequencing of their exome. Among the 213 genes in which at least one variant was present, the most interesting was found gene NRAS, one of the most often mutated gene in multiple myeloma, and homologs of 88 gene panel previously used for multiple myeloma sequencing among which was a gene previously identified as gene meaningful in bortezomib resistance. Nevertheless, the results of next generation exome sequencing need to be interpreted with caution, since they rely on bioinformatical analysis, which is still being optimized. The results of next generation sequencing will also have to be confirmed by Sanger sequencing. Final results supported by larger cohort of patients will be published soon.Key words: multiple myeloma - minimal residual disease - exome - next generation sequencing.