Microenvironment-induced PIM kinases promote CXCR4-triggered mTOR pathway required for chronic lymphocytic leukaemia cell migration.

Lymph node microenvironment provides chronic lymphocytic leukaemia (CLL) cells with signals promoting their survival and granting resistance to chemotherapeutics. CLL cells overexpress PIM kinases, which regulate apoptosis, cell cycle and migration. We demonstrate that BCR crosslinking, CD40 stimulation, and coculture with stromal cells increases PIMs expression in CLL cells, indicating microenvironment-dependent PIMs regulation. PIM1 and PIM2 expression at diagnosis was higher in patients with advanced disease (Binet C vs. Binet A/B) and in those, who progressed after first-line treatment. In primary CLL cells, inhibition of PIM kinases with a pan-PIM inhibitor, SEL24-B489, decreased PIM-specific substrate phosphorylation and induced dose-dependent apoptosis in leukaemic, but not in normal B cells. Cytotoxicity of SEL24-B489 was similar in TP53-mutant and TP53 wild-type cells. Finally, inhibition of PIM kinases decreased CXCR4-mediated cell chemotaxis in two related mechanisms-by decreasing CXCR4 phosphorylation and surface expression, and by limiting CXCR4-triggered mTOR pathway activity. Importantly, PIM and mTOR inhibitors similarly impaired migration, indicating that CXCL12-triggered mTOR is required for CLL cell chemotaxis. Given the microenvironment-modulated PIM expression, their pro-survival function and a role of PIMs in CXCR4-induced migration, inhibition of these kinases might override microenvironmental protection and be an attractive therapeutic strategy in this disease.

Comprehensive histopathological diagnostics of aggressive B-cell lymphomas based on the updated criteria of the World Health Organisation's 2017 classification.

Revision of the fourth edition of the World Health Organisation (WHO) Classification of Haematopoietic and Lymphatic Tissues, which was published in 2017, introduced important changes updating the biology, pathology, genetics, and clinical presentation of aggressive B-cell lymphomas. High grade B-cell lymphomas (HGBLs) replaced B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma, the new provisional entity Burkitt-like lymphoma with 11q aberration was identified, and some categories were upgraded, e.g. EBV-positive diffuse large B-cell lymphoma, not otherwise specified. Still the histopathological diagnostics is based on morphology and immunoprofile, but to define the HGBLs evaluation of MYC, BCL2, and BCL6 gene statuses is required. According to the presented WHO criteria, in the comprehensive histopathological diagnostics of aggressive B-cell lymphomas a highly specialised diagnostic team including a pathologist, a molecular biologist, a geneticist, a haematologist, and immunophenotyping technicians is needed.

BCRP mRNA and FLT3-ITD are independent poor risk factors in adult patients with acute myeloid leukemia and intermediate or normal karyotype.

PURPOSE: FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is aberration associated with poor prognosis in AML. We have analyzed the expression of MDR-1, MRP-1, and BCRP mRNA in relation to FLT3-ITD in 100 AML adult patients with normal and intermediate karyotype. METHODS: The RQ-PCR method was performed to assess the expression of MDR-1, MRP-1, and BCRP mRNA, and the results were presented as coefficients calculated using an intermediate method according to Pfaffl's rule. RESULTS: According to univariate analysis, the following pretreatment variables negatively influenced disease-free survival (DFS): WBC count ≥25×109 /L (P=.037), MRP-1 mRNA ≥1.6818 (P=.028), BCRP mRNA ≥1.1892 (P=.004), FLT3-ITD (P=.005) and overall survival (OS): WBC count ≥25×109 /L (P=.031), MRP-1 mRNA ≥1.6818 (P=.01), BCRP mRNA ≥1.1892 (P=.01), FLT3-ITD (P=.001). When all prognostic variables were pooled into a multivariate model, we found that WBC count ≥25×109 /L (P=.026) and BCRP mRNA ≥1.1892 (P=.011). We observed trend in negative influence of FLT3-ITD on DFS (P=.057). BCRP mRNA ≥1.1892 (P=.035) and FLT3-ITD (P=.006) negatively, independently influenced the OS. CONCLUSIONS: The high expressions of BCRP mRNA calculated with Pfaffl's rule and FLT3-ITD are independent poor risk factors in adult patients with AML and intermediate or normal karyotype.

Comparison of high-resolution melting analysis with direct sequencing for the detection of recurrent mutations in DNA methyltransferase 3A and isocitrate dehydrogenase 1 and 2 genes in acute myeloid leukemia patients.

Acute myeloid leukemia (AML) cells harbor frequent mutations in genes responsible for epigenetic modifications. Increasing evidence of clinical role of DNMT3A and IDH1/2 mutations highlights the need for a robust and inexpensive test to identify these mutations in routine diagnostic work-up. Herein, we compared routinely used direct sequencing method with high-resolution melting (HRM) assay for screening DNMT3A and IDH1/2 mutations in patients with AML. We show very high concordance between HRM and Sanger sequencing (100% samples for IDH2-R140 and DNMT3-R882 mutations, 99% samples for IDH1-R132 and IDH2-R172 mutations). HRM method reported no false-negative results, suggesting that it can be used for mutations screening. Moreover, HRM displayed much higher sensitivity in comparison with DNA sequencing in all assessed loci. With Sanger sequencing, robust calls were observed when the sample contained 50% of mutant DNA in the background of wild-type DNA. In marked contrast, the detection limit of HRM improved down to 10% of mutated DNA. Given the ubiquitous presence of wild-type DNA background in bone marrow aspirates and clonal variations regarding mutant allele burden, these results favor HRM as a sensitive, specific, labor-, and cost-effective tool for screening and detection of mutations in IDH1/2 and DNMT3A genes in patients with AML.

Mild chronic graft-versus-host disease may alleviate poor prognosis associated with FLT3 internal tandem duplication for adult acute myeloid leukemia following allogeneic stem cell transplantation with myeloablative conditioning in first complete remission: a retrospective study.

Internal tandem duplication (ITD) of the FLT3 gene (Fms-like tyrosine kinase 3) is the most commonly found mutation in acute myeloid leukemia (AML). The significance of FLT3-ITD at diagnosis was retrospectively estimated for allo-HSCT (allogeneic hematopoietic stem cell transplantation) outcomes in 140 patients, median age of 38, undergoing allo-HSCT after myeloablative conditioning in first complete remission of AML. FLT3-ITD was detected at AML diagnosis in 42/140 (30%) of included into this study patients. At 3 years, relapse incidence (RI) following allo-HSCT in AML patients with intermediate or normal karyotype was significantly higher in those FLT3-ITD positive than FLT3-ITD negative [52.9 vs. 20.4%, P = 0.002]. Additionally, patients with mild chronic graft-versus-host disease (cGvHD) had significantly lower RI compared to patients with moderate or severe grade cGvHD or those not experiencing cGvHD, respectively, 4.8 vs. 36.0 vs. 27.8%, P = 0.032. FLT3-ITD was harboring a poor prognosis in AML with intermediate or normal karyotype and significantly increased risk of relapse following allo-HSCT. It appears that allo-HSCT does not cure patients with FLT3-ITD, unless they develop symptoms of mild cGvHD and graft versus leukemia, which may decrease RI.

CEBPA copy number variations in normal karyotype acute myeloid leukemia: Possible role of breakpoint-associated microhomology and chromatin status in CEBPA mutagenesis.

Copy number variations (CNV) in CEBPA locus represent heterogeneous group of mutations accompanying acute myeloid leukemia (AML). The aim of this study was to characterize different CEBPA mutation categories in regard to biological data like age, cytology, CD7, and molecular markers, and identify possible factors affecting their etiology. We report here the incidence of 12.6% of CEBPA mutants in the population of 262 normal karyotype AML (NK-AML) patients. We confirmed that double mutant AMLs presented uniform biological features when compared to single CEBPA mutations and accompanied mostly younger patients. We hypothesized that pathogenesis of distinct CEBPA mutation categories might be influenced by different factors. The detailed sequence analysis revealed frequent breakpoint-associated microhomologies of 2 to 12bp. The analysis of distribution of microhomology motifs along CEBPA gene showed that longer stretches of microhomology at the mutational junctions were relatively rare by chance which suggests their functional role in the CEBPA mutagenesis. Additionally, accurate quantification of CEBPA transcript levels showed that double CEBPA mutations correlated with high-level CEBPA expression, whereas single N-terminal CEBPA mutations were associated with low-level CEBPA expression. This might suggest that high-level CEBPA expression and/or accessibility of CEBPA locus contribute to B-ZIP in-frame duplications.

Prognostic Impact of Copy Number Alterations' Profile and AID/RAG Signatures in Acute Lymphoblastic Leukemia (ALL) with BCR::ABL and without Recurrent Genetic Aberrations (NEG ALL) Treated with Intensive Chemotherapy.

Adult acute lymphoblastic leukemia (ALL) is associated with poor outcomes. ALL is initiated by primary aberrations, but secondary genetic lesions are necessary for overt ALL. In this study, we reassessed the value of primary and secondary aberrations in intensively treated ALL patients in relation to mutator enzyme expression. RT-PCR, genomic PCR, and sequencing were applied to evaluate primary aberrations, while qPCR was used to measure the expression of RAG and AID mutator enzymes in 166 adult ALL patients. Secondary copy number alterations (CNA) were studied in 94 cases by MLPA assay. Primary aberrations alone stratified 30% of the patients (27% high-risk, 3% low-risk cases). The remaining 70% intermediate-risk patients included BCR::ABL1pos subgroup and ALL lacking identified genetic markers (NEG ALL). We identified three CNA profiles: high-risk bad-CNA (CNAhigh/IKZF1pos), low-risk good-CNA (all other CNAs), and intermediate-risk CNAneg. Furthermore, based on RAG/AID expression, we report possible mechanisms underlying the CNA profiles associated with poor outcome: AID stratified outcome in CNAneg, which accompanied most likely a particular profile of single nucleotide variations, while RAG in CNApos increased the odds for CNAhigh/IKZF1pos development. Finally, we integrated primary genetic aberrations with CNA to propose a revised risk stratification code, which allowed us to stratify 75% of BCR::ABL1pos and NEG patients.

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.

Targeting arginase-1 exerts antitumor effects in multiple myeloma and mitigates bortezomib-induced cardiotoxicity.

Multiple myeloma (MM) remains an incurable malignancy of plasma cells despite constantly evolving therapeutic approaches including various types of immunotherapy. Increased arginase activity has been associated with potent suppression of T-cell immune responses in different types of cancer. Here, we investigated the role of arginase 1 (ARG1) in Vκ*MYC model of MM in mice. ARG1 expression in myeloid cells correlated with tumor progression and was accompanied by a systemic drop in ʟ-arginine levels. In MM-bearing mice antigen-induced proliferation of adoptively transferred T-cells was strongly suppressed and T-cell proliferation was restored by pharmacological arginase inhibition. Progression of Vκ*MYC tumors was significantly delayed in mice with myeloid-specific ARG1 deletion. Arginase inhibition effectively inhibited tumor progression although it failed to augment anti-myeloma effects of bortezomib. However, arginase inhibitor completely prevented development of bortezomib-induced cardiotoxicity in mice. Altogether, these findings indicate that arginase inhibitors could be further tested as a complementary strategy in multiple myeloma to mitigate adverse cardiac events without compromising antitumor efficacy of proteasome inhibitors.

IDH2 mutations in patients with normal karyotype AML predict favorable responses to daunorubicin, cytarabine and cladribine regimen.

Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) genes occur in about 20% patients with acute myeloid leukemia (AML), leading to DNA hypermethylation and epigenetic deregulation. We assessed the prognostic significance of IDH1/2 mutations (IDH1/2+) in 398 AML patients with normal karyotype (NK-AML), treated with daunorubicine + cytarabine (DA), DA + cladribine (DAC), or DA + fludarabine. IDH2 mutation was an independent favorable prognostic factor for 4-year overall survival (OS) in total NK-AML population (p = 0.03, censoring at allotransplant). We next evaluated the effect of addition of cladribine to induction regimen on the patients' outcome according to IDH1/2 mutation status. In DAC group, 4-year OS was increased in IDH2+ patients, compared to IDH-wild type group (54% vs 33%; p = 0.0087, censoring at allotransplant), while no difference was observed for DA-treated subjects. In multivariate analysis, DAC independently improved the survival of IDH2+ patients (HR = 0.6 [0.37-0.93]; p = 0.024; censored at transplant), indicating that this group specifically benefits from cladribine-containing therapy. In AML cells with R140Q or R172K IDH2 mutations, cladribine restrained mutations-related DNA hypermethylation. Altogether, DAC regimen produces better outcomes in IDH2+ NK-AML patients than DA, and this likely results from the hypomethylating activity of cladribine. Our observations warrant further investigations of induction protocols combining cladribine with IDH1/2 inhibitors in IDH2-mutant.

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.

Novel mutation of IL1RAPL1 gene in a nonspecific X-linked mental retardation (MRX) family.

Mental retardation (MR) affects approximately 2% of the population. About 10% of all MR cases result from defects of X-linked genes. Mutations in most of more than 20 known genes causing nonspecific form of X-linked MR (MRX) are very rare and may account for less than 0.5-1% of MR. Linkage studies in extended pedigrees followed by mutational analysis of known MRX genes in the linked interval are often the only way to identify a genetic cause of the disorder. We performed linkage analysis in several MRX families, and in one family with four males with MR we mapped the disease to an interval encompassing Xp21.2-22.11 (with a maximum LOD score of 2.71). Subsequent mutation analysis of genes located in this interval allowed us to identify a partial deletion of the IL1RAPL1 gene. Different nonoverlapping deletions involving IL1RAPL1 have been reported previously, suggesting that this region could be deletion-prone. In this report, we present the results of the molecular analyses and clinical examinations of four affected family members with the deletion in IL1RAPL1. Our data further confirm the importance and usefulness of linkage studies for gene mapping in MRX families and demonstrate that IL1RAPL1 plays an important role in the etiology of MRX. With the development of new methods (aCGH, MLPA), further rearrangements in this gene (including deletions and duplications) might be discovered in the nearest future.

Promoter DNA methylation and expression levels of HOXA4, HOXA5 and MEIS1 in acute myeloid leukemia.

HOXA genes encode transcription factors, which are crucial for embryogenesis and tissue differentiation and are involved in the early stages of hematopoiesis. Aberrations in HOXA genes and their cofactor MEIS1 are found in human neoplasms, including acute myeloid leukemia (AML). The present study investigated the role of HOXA4, HOXA5 and MEIS1 promoter DNA methylation and mRNA expression in AML. Samples from 78 AML patients and 12 normal bone marrow (BM) samples were included. The levels of promoter DNA methylation were determined using quantitative methylation­specific polymerase chain reaction (PCR; qMSP) and the relative expression levels were measured using reverse transcription quantitative PCR in Ficoll­separated BM mononuclear cells and in fluorescent activated cell sorting­sorted populations of normal hematopoietic progenitors. In total, 38.1 and 28.9% of the patients exhibited high methylation levels of HOXA4 and HOXA5, respectively, compared with the control samples, and MEIS1 methylation was almost absent. An inverse correlation between HOXA4 methylation and expression was identified in a group of patients with a normal karyotype (NK AML). An association between the genes was observed and correlation between the DNA methylation and expression levels of the HOXA gene promoter with the expression of MEIS1 was observed. Patients with favorable chromosomal aberrations revealed a low level of HOXA4 methylation and decreased expression levels of HOXA5 and MEIS1 compared with the NK AML and the adverse cytogenetic risk patients. The NK AML patients with NPM1 mutations exhibited elevated HOXA4 methylation and expression levels of HOXA5 and MEIS1 compared with the NPM1 wild­type patients. Comparison of the undifferentiated BM­derived hematopoietic CD34+CD38low, CD34+CD38+ and CD15+ cells revealed a gradual decrease in the expression levels of these three genes and an increase in HOXA4 promoter methylation. This differentiation­associated variability was not observed in AML, which was classified according to the French­American­British system.

Comparison of promoter DNA methylation and expression levels of genes encoding CCAAT/enhancer binding proteins in AML patients.

CCAAT/enhancer binding proteins (CEBPs) are transcription factors regulating myeloid differentiation. Disturbances of their expression may contribute to leukemogenesis. In this study we compared promoter methylation and expression levels of selected CEBP genes in a group of 78 AML patients, normal bone marrow and hematopoietic precursor cells. CEBPA, CEBPD and CEBPE promoter methylation levels were elevated in 37%, 35.5% and 56.7% of patients. No CEBPZ(DDIT3) methylation was observed. An inverse relationship between CEBPA and CEBPD DNA methylation and expression levels was observed. AML cytogenetic risk groups and patients with particular translocation are characterized by distinct methylation/expression profile of CEBPs encoding genes.

Acute panmyelosis with myelofibrosis with EVI1 amplification.

EVI1 is located on chromosome 3q26 and is up-regulated mostly through an inv(3)(q21q26) or t(3;3)(q21;q26). Chromosomal aberrations involving 3q26 comprise 1-2% of all acute myeloid leukemia (AML). These changes result in overexpression of the EVI1 oncogene. EVI1 transcriptional activation has been reported in up to 10% of AML patients, even in the absence of 3q26 changes, and is an independent indicator of adverse prognosis. Rearrangements of the EVI1 locus are often associated with monosomy 7. We present a case of acute panmyelosis with myelofibrosis with a unique EVI1 amplification within a derivative 8 chromosome, characterized by karyotyping and fluorescence in situ hybridization, conventional high resolution comparative genomic hybridization, as well as by gene expression studies. We conclude that EVI1 overexpression as a consequence of EVI1 gene amplification causes similar biological effects to the changes caused by the typical 3q26 aberrations such as an inv(3)(q21q26) or t(3;3)(q21;q26) with EVI1 gene rearrangements.

[Balanced chromosomal rearrangements resulting in intellectual disability. An analysis of 22 cases with application of CGH and FISH methods]. / Zrównowazone rearanzacje chromosomowe jako przyczyna niepelnosprawnosci intelektualnej. Analiza 22 przypadków z wykorzystaniem technik CGH oraz FISH.

INTRODUCTION: In approximately 6% of balanced chromosomal rearrangements carriers, intellectual disability, dysmorphic features and congenital anomalies can be found. The abnormal phenotype might be the result of genomic imbalance or aberrant expression caused by direct breakage of a dosage sensitive gene. THE AIM OF THIS STUDY: To estimate the frequency and implication of the submicroscopic chromosomal aberrations on the abnormal phenotypes present in patients with balanced chromosomal rearrangements. Also an attempt was made to define the type of genetic defect and gene identification responsible for the intellectual disability and additional clinical features. MATERIAL AND METHODS: 22 patients with intellectual disability, congenital anomalies and dysmorphic features were analysed. Molecular karyotyping was performed in all patients using FISH with region-specific BAC clones, high resolution comparative genomic hybridization (HR-CGH) or array CGH (aCGH). A targeted or whole genome microarrays were applied. RESULTS: In 5 of 22 carriers 6 microdeletions and one duplication were found (7/22, 31.8%). Only two microdeletions were mapped at the chromosomal breakpoints. Three rearrangements had more complex structure than conventional methods demonstrated. In the chromosomal breakpoints of 21 patients the 24 genes, which functions suggest the relationship between abnormal gene expression and patients' intellectual disability, were mapped. CONCLUSIONS: We showed that in a considerable group of patients with balanced chromosomal rearrangements and abnormal phenotype the cryptic aberrations, unidentified by conventional methods, are present. These results confirmed the legitimacy of detailed analysis of the chromosomal breakpoints as well as the whole genome screening with the use of new cytogenetic methods.