Acute mast cell leukemia without KIT D816V mutation and lack of CD2 and CD25-a case report of rare entity.

Systemic mastocytosis (SM) is a rare hematological neoplasm caused by the excessive proliferation of pathological mast cells that accumulate in the bone marrow (BM) and other extracutaneous organs leading to multi-organ damage and failure. Mast cell leukemia (MCL) is a rare form of systemic mastocytosis, accounting for < 1% of all cases of mastocytosis. MCL usually behaves aggressively with poor responses to current treatment options. Here, we report a diagnostic challenge with the leukemic subtype of MCL with a primary suspicion of pancreatic cancer. A cytomorphological, immunophenotypic, and histopathological examination of the bone marrow was performed. The diagnosis was based on the presence of ≥ 20% atypical and immature mast cells in the bone marrow and ≥ 10% mast cells among the peripheral white blood cells. The neoplastic cell population was identified as mast cell lineage by the expression of CD117 and tryptase. Only 3% of neoplastic cells displayed surface markers characteristic for clonal mast cells: CD25 and CD2. The D816V KIT mutation was not found. Neoplastic mast cells expressed CD30, a marker that is currently considered as a new minor criterion for SM. In the presented case, the primary suspicion of pancreatic cancer with osteosclerotic, lung, and pleural metastases was misleading, and a differential diagnosis based on hematological findings was performed. The patient's severe symptoms were likely the result of organ damage from mast cell infiltration. Despite the use of intensive acute myeloid leukemia (AML)-like polychemotherapy, the patient died during the course of post-induction myelosuppression due to bleeding complications.

Tracking Clonal Evolution of Multiple Myeloma Using Targeted Next-Generation DNA Sequencing.

Clonal evolution drives treatment failure in multiple myeloma (MM). Here, we used a custom 372-gene panel to track genetic changes occurring during MM progression at different stages of the disease. A tumor-only targeted next-generation DNA sequencing was performed on 69 samples sequentially collected from 30 MM patients. The MAPK/ERK pathway was mostly affected with KRAS mutated in 47% of patients. Acquisition and loss of mutations were observed in 63% and 37% of patients, respectively. Four different patterns of mutation evolution were found: branching-, mutation acquisition-, mutation loss- and a stable mutational pathway. Better response to anti-myeloma therapy was more frequently observed in patients who followed the mutation loss-compared to the mutation acquisition pathway. More than two-thirds of patients had druggable genes mutated (including cases of heavily pre-treated disease). Only 7% of patients had a stable copy number variants profile. Consequently, a redistribution in stages according to R-ISS between the first and paired samples (R-ISS″) was seen. The higher the R-ISS″, the higher the risk of MM progression and death. We provided new insights into the genetics of MM evolution, especially in heavily pre-treated patients. Additionally, we confirmed that redefining R-ISS at MM relapse is of high clinical value.

Immunophenotypic Characteristics of Bone Marrow Microenvironment Cellular Composition at the Biochemical Progression of Multiple Myeloma.

Multiple myeloma (MM) relapses are inevitable in the majority of patients, and in addition to genetic changes in the MM clone, the immune profile of the bone marrow (BM) plays a key role in this process. Biochemical progression or relapse (BR) precedes clinical relapse in a significant proportion of patients with MM. In the present study, we used flow cytometry to assess the cellular composition of the BM microenvironment in MM patients with confirmed BR. Fifteen distinct cells subsets in the BM were evaluated with the panel of antibodies used routinely for MRD monitoring in MM in 52 patients with MM (MRD-negative n = 20, BR n = 20, and clinically relapsed MM, RMM n = 12). The median percentage of MM cells detected in BR patients was 0.90% versus not detectable in MRD-negative patients and of 3.0% in RMM cohort. Compared to the MRD-negative group, BR status was associated with an increase in the percentage of lymphoid subpopulations, including memory B cells (p = 0.003), CD27+T cells (p = 0.002), and NK/NKT cells (p < 0.001). Moreover, a decrease in B-cell precursors (p < 0.001) and neutrophils (p = 0.006) was observed. There were no significant differences in the composition of the BM cell subpopulations between the BR and RMM groups. Our results indicate the involvement of B-, T-, and NK cells in the process of losing immune surveillance over the MM clone that leads to relapse. It can be speculated that similar studies of a larger cohort of BR patients can potentially identify a group of patients for which an early treatment intervention would be beneficial.

Persistent imbalance, anti-apoptotic, and anti-inflammatory signature of circulating C-C chemokines and cytokines in patients with paroxysmal nocturnal hemoglobinuria.

OBJECTIVE: Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal non-malignant disease in which hematopoietic cell apoptosis may play an important pathophysiological role. Previous studies of the content of phosphatidylinositol (3,4,5)-trisphosphate (PI(3,4,5)P3) indicated the possibility of remote transmission of anti-apoptotic signals between pathological and normal hematopoietic progenitors. METHODS: The study determined the plasma levels of beta chemokines and cytokines in N = 19 patients with PNH and 31 healthy controls. The research material was peripheral blood plasma (EDTA) stored at -80 °C until the test. Beta chemokine and cytokine concentrations were tested in duplicate with Bio-Plex Pro Human Cytokine Assay (Bio-Rad, Hercules, CA, USA) using a Luminex 200 flow cytometer and xPONENT software (Luminex Corporation, Austin, TX, USA). In peripheral blood CD34+ cells we tested the proportions of PI(3,4,5)P3+ and Annexin binding apoptotic phenotype using FC and phosflow. RESULTS: Compared to the control group, the PNH group showed a significant increase in the plasma concentration of some beta chemokines and cytokines, including MIP-1alpha/CCL3, eotaxin/CCL11, MCP1/CCL2, IL4 and G-CSF. In the group of PNH patients, a significant decrease in the concentration of some cytokines was also observed: RANTES/CCL5, MIP-1beta/CCL4, PDGF-BB and IL9. At the same time, the plasma concentrations of the chemokine IP-10/CXCL10 and the cytokines IFN-gamma, TNF, IL6 and IL10 showed no significant deviations from the values for the control group. Anti-apoptotic phenotype and phosphatidylinositol (3,4,5)-trisphosphate content in PNH clone of CD34+ cells were associated with the level of CCL3 and negatively associated with CCL5, CCL4, PDGF-BB and IL9. CONCLUSIONS: This data suggest the existence of apoptotic and PI(3,4,5)P3 imbalance in PNH CD34+ cells driven by anti-apoptotic cytokine biosignature in PNH. Plasma cytokines and intracellular enzymes that regulate the phosphoinositide pathways may become a therapeutic target in PNH.

Harmonization of Flow Cytometric Minimal Residual Disease Assessment in Multiple Myeloma in Centers of Polish Myeloma Consortium.

Minimal residual disease (MRD) status is now considered as one of the most relevant prognostic factors in multiple myeloma (MM) while MRD negativity became an important endpoint in clinical trials. Here, we report the results of the first study evaluating the reproducibility of high-sensitivity flow cytometry MM MRD assessment in four laboratories in Poland. EuroFlow protocols for instrument setting standardization and sample preparation in MM MRD assessment were implemented in each laboratory. In the inter-laboratory reproducibility study, 12 bone marrow samples from MM patients were distributed and processed in participant laboratories. In the inter-operator concordance study, 13 raw data files from MM MRD measurements were analyzed by five independent operators. The inter-laboratory study showed high 95% overall concordance of results among laboratories. In the inter-operator study, 89% of MRD results reported were concordant, and the highest immunophenotype interpretation differences with regard to expression of CD27, CD45, CD81 were noticed. We confirmed the applicability and feasibility of the EuroFlow protocol as a highly sensitive method of MRD evaluation in MM. Results of our inter-center comparison study demonstrate that the standardization of MM MRD assessment protocols is highly desirable to improve quality and comparability of results within and between different clinical trials.

The impact of cytogenetic evolution and acquisition of del(17p) on the prognosis of patients with multiple myeloma.

INTRODUCTION: Prognosis of patients with newly diagnosed multiple myeloma (MM), a third most common hematological cancer, is dependent on baseline cytogenetics. However, little is known about the prognostic significance of cytogenetic evolution (CE) at the time between the diagnosis and relapse of MM. OBJECTIVES: Here, we retrospectively analyzed the prognostic impact of CE detected in a routine interphase fluorescence in situ hybridization (FISH) test in a cohort of patients with MM. PATIENTS AND METHODS: Among 650 patients evaluated with the FISH MM panel at our center between 2014 and 2019, we identified 29 individuals with MM who had been tested twice, at the time of diagnosis and relapse. Cytogenetic evolution was defined as the acquisition or loss of at least 1 cytogenetic abnormality at relapse (FISH2) compared with the baseline test result (FISH1). RESULTS: Cytogenetic evolution was seen in 14 patients (48%), whereas 15 had stable cytogenetics. Acquired chromosome 17p deletion (del[17p]) was the most common type of CE, found in 7 patients (24%). In univariable analysis, stable cytogenetics predicted longer overall survival (median not reached vs 3.8 years; hazard ratio [HR], 0.15; P = 0.04; median follow­up of 3.1 years) and longer overall survival after FISH2 (median not reached vs 0.8 years; HR, 0.13; P = 0.002; median follow­up of 0.6 years). In multivariable analysis, acquired del(17p) predicted shorter progression­free survival and the overall survival after FISH2 (HR, 9.3 and 18.8; P = 0.005 and P = 0.004, respectively). CONCLUSIONS: Presence of CE and, particularly, the acquisition of new del(17p) at relapse, negatively affect the outcome of MM. Therefore, re­evaluation of FISH at MM relapse should be included in routine clinical practice.