Characteristics and treatment results of refractory and relapsed acute myeloid leukaemia in paediatric patients treated in Polish Paediatric Leukaemia/Lymphoma Study Group institutions according to the Protocol Acute Myeloid Leukaemia Berlin-Frankfurt-Munster 2012 and a review of novel treatment possibilities in paediatric acute myeloid leukaemia.

Introduction: This study aimed to present the clinical features and results of treatment of patients diagnosed with refractory or relapsed acute myeloid leukaemia (AML) in Polish Paediatric Leukaemia/Lymphoma Study Group (PPL/LSG) institutions, treated in accordance with the Protocol Acute Myeloid Leukaemia Berlin-Frankfurt-Munster 2012, as their first-line therapy. Material and methods: The outcome data of 10 patients with refractory AML (median age 9.5 years) and 30 with relapsed AML (median age 12 years) were analysed retrospectively. Re-induction was usually based on idarubicin, fludarabine, and cytarabine along with allogeneic haematopoietic stem cell transplant (allo-HSCT) in 5 patients with refractory AML and 7 relapsed AML children. Results: 37.5% (3/8) of refractory AML patients achieved second complete remission second complete remission (CRII). One of ten patients (1/10; 10%) was alive and stayed in complete remission for 34 months after the allo-HSCT. The probability of 3-year event-free survival (pEFS) in this group was 0.125 ±0.11. In the group of relapsed AML patients, the CRII was achieved in 9 patients (34%), and the probability of survival was: pEFS = 0.24 ±0.08; probability overall survival (pOS) = 0.34 ±0.09, with significantly better results achieved in patients who underwent allo-HSCT (pOS = 0.54 ±0.14 vs. 0.08 ±0.08, p < 0.0001). Conclusions: The prognosis of refractory AML and the first AML recurrence in children who were first-line treated in PPL/LSG centres according to Protocol Acute Myeloid Leukaemia Berlin-Frankfurt-Munster 2012 is poor. Failures of re-induction treatment particularly result from difficulties in achieving remission. Allogeneic HSCT improves prognosis in children with refractory and first recurrent AML, under the condition it is performed in complete remission. Novel therapeutic approaches are needed to increase the remission rate and improve the outcomes.

Analysis of incidence and risk factors of the multidrug resistant gastrointestinal tract infection in children and adolescents undergoing allogeneic and autologous hematopoietic cell transplantation: a nationwide study.

The aim of this multi-center study was to evaluate the incidence, clinical course, and risk factors for bacterial multidrug-resistant (MDR) gastrointestinal tract infections (GTI) among children undergoing allogeneic and autologous hematopoietic cell transplantation. A total number of 175 pediatric patients (aged 1-18 years), transplanted between January 2018 and December 2019, who were tested for bacterial colonization/infection were enrolled into this multi-center analysis. Episodes of MDR GTI occurred in 77/175 (44%) patients. In multivariate analysis for higher GTI incidence, the following factors were significant: matched-unrelated donor (MUD) transplantation, HLA mismatch, presence of graft-versus-host disease (GVHD), and gut GVHD. The most common GTI were Clostridium difficile (CDI), multidrug-resistant Enterobacteriaceae (Klebsiella pneumoniae, Escherichia coli extended-spectrum ß-lactamase), and Enterococcus HLAR (high-level aminoglycoside-resistant). No MDR GTI-attributed deaths were reported. MDR GTI is a frequent complication after HCT among children, causes prolonged hospitalization, but rarely contributes to death. We identified risk factors of MDR GTI development in children, with focus on GVHD and unrelated donor and HLA mismatch. We conclude that the presence of Clostridiales plays an important anti-inflammatory homeostatic role and decreases incidence of GVHD or alleviate its course.

Prospective analysis of BKV hemorrhagic cystitis in children and adolescents undergoing hematopoietic cell transplantation.

BK virus is one of the most common causes of hemorrhagic cystitis (HC) in children undergoing hematopoietic cell transplantation (HCT). Viruses can be found in urine and serum samples of immunocompromised patients. Malignant diseases, age, cell source, day of granulocyte reconstitution, conditioning regimen, or use of total body irradiation may play an important role in BKV epidemiology, development of hemorrhagic cystitis course, and outcome. The aim of this study was to evaluate the incidence, clinical course, and risk factors for BKV-HC in children undergoing HCT. A total number of 133 patients who were prospectively tested for BKV colonization/infection were enrolled into this multicenter analysis. Episodes of BKV-HC occurred in 36/133 (27%) enrolled subjects. In a univariate analysis for BKV-HC incidence, the following factors were significant: age >5 years, peripheral blood transplantation, matched unrelated donor (MUD) transplantation, busulfan-cyclophosphamide-melphalan conditioning regimen, and acute myeloblastic leukemia (AML) diagnosis. Presence of acute graft-versus-host disease (aGVHD) in liver and gut GVHD was a significant risk factor of BKV-HC. No BKV-attributed deaths were reported. In multivariate analysis, the incidence of HC was significantly higher in patients with AML, age >5 years, MUD transplants, and children with GVHD. HC is a frequent complication after HCT among children causes prolonged hospitalization but rarely contributes to death. We identified risk factors of BKV-HC development in children, with focus on aGVHD: we concluded that excessive immune reaction connected with GVHD and immunosuppression drugs might play a pivotal role in the development of BKV-HC.

Killer-cell immunoglobulin-like receptor genotype and haplotype combinations in children treated for acute lymphoblastic leukemia.

INTRODUCTION: Acute lymphoblastic leukemia (ALL) is the most common malignancy diagnosed in children. The factors predisposing to ALL remain mostly unknown. Natural killer (NK) cells are a component of innate immunity. Their role is to eliminate cells that were infected with viruses or underwent a neoplastic transformation. The activity of NK cells is regulated by their activating and inhibitory receptors, inter alia killer-cell immunoglobulin-like receptors (KIRs). The available data about a link between the incidence of ALL and KIR genotype are highly inconclusive, and further research is needed to explain whether such a relationship truly exists. The aim of this study was to analyze KIR genotype and haplotype combinations in children treated for ALL. MATERIAL AND METHODS: The study included 49 children diagnosed with ALL at 1.2-19.8 years of age. The control group was composed of 43 healthy subjects aged between 1.2 and 21.9 years. DNA was isolated using QIAamp DNA Mini kits. KIR genotypes were identified by a polymerase chain reaction (PCR) with sequence-specific primers (SSPs). The analysis also included KIR haplotype combinations: AA, AB and BB. RESULTS: Patients with ALL and controls did not differ significantly in the frequencies of individual KIR genes and haplotypes. However, the overall frequency of all 6 activating KIR genes in patients with ALL was significantly higher than in the controls (24.5% vs. 4.7%, p = 0.019). CONCLUSIONS: The findings presented here imply that individual KIR genes do not play a significant role in the pathogenesis of ALL. Nevertheless, a higher number of activating KIR genes may constitute a risk factor for this malignancy.

Common variable immunodeficiency: different faces of the same disease.

INTRODUCTION: Common variable immunodeficiency (CVID) is one of the primary humoral immunodeficiencies. Despite the inborn nature, the first symptoms may appear in both children and adults. It is characterized by hypogammaglobulinaemia, severe infections, autoimmunity, allergies, and a predisposition to cancer. A delay in diagnosis is a significant problem: the time from the first symptoms of the disease to diagnosis and the implementation of proper treatment is usually very long. The consequence can be irreversible complications, which is why it is so important to promote knowledge on this immunodeficiency. AIM: To present the clinical and laboratory manifestation of primary immunodeficiencies such as common variable immunodeficiency. MATERIAL AND METHODS: The study presents the clinical and laboratory phenotype of 14 patients diagnosed with CVID, aged 5 to 58 years. A detailed medical history was taken, and clinical symptoms, immunological test results and complications were analysed in each patient. According to the ESID guidelines, in the differential diagnosis process of CVID the secondary hypogammaglobulinaemia was excluded. RESULTS: The follow-up period ranged from 39 to 133 months (median: 79 months). The median delay for the entire group was 5 years, which was shorter in children than in adults. In the presented group, the infectious phenotype (pneumonia, sinusitis) was dominant. Autoimmune and allergic diseases, malignant tumours and enteropathies have also been observed. CONCLUSIONS: The diagnostic delay is still too long, especially in adults, which can lead to serious and irreversible complications. Early diagnosis and appropriate treatment with intravenous and subcutaneous immunoglobulins reduces the frequency of infections and their potential complications.

Mixed phenotype acute leukemia: Biological profile, clinical characteristic and treatment outcomes: Report of the population-based study.

OBJECTIVES: The aim of this population-based, retrospective study was to analyze biological and clinical features and treatment results in children diagnosed with MPAL in all Polish pediatric oncology centers between 2007 and 2018. METHODS: Among 2893 children and adolescents diagnosed and treated for acute leukemia, 39 (1.35%) patients fulfilled the WHO criteria of MPAL. The T/myeloid phenotype was most prevalent. RESULTS: Cytogenetics findings were seen in 2 (5.1%), while chromosomal abnormalities were found in 14 (35.9%) patients. Thirty-two patients achieved CR-1, including 23 (92.0%) treated with ALL-directed chemotherapy and 9 (64.3%) treated with AML-type induction regimens. Within these patients, 4 (12.5%) died due to treatment-related complications and 11 (34.4%) relapsed. Nineteen (63.3%) patients underwent allo-HSCT in CR-1 and 14 (73.7%) of them have been in CR-1. In total, 17 (43.6%) patients remain in CR-1 for 1-12 years, including 14 (58.3%) with T/myeloid MPAL. The 5-year pOS and pEFS were 51.8% and 44.2%, respectively. The overall survival for ALL-directed therapy was significantly better than the one for AML-type chemotherapy (P = .001). It was also better for patients who underwent HSCT in CR-1 (P = .001). CONCLUSIONS: The prognosis of MPAL is unsatisfactory, but initial treatment with ALL-directed chemotherapy consolidated with allo-HSCT improves the outcomes in MPAL.

Infectious complications after hematopoietic stem cell transplantation for primary immunodeficiency in children: A multicenter nationwide study.

PURPOSE: The aim of this nationwide study was to evaluate the characteristics of bacterial infections (BI), invasive fungal disease (IFD), and viral infections (VI) in pediatric patients with PID after allogeneic hematopoietic stem cell transplantation (allo-HSCT). PATIENTS AND METHODS: In total, 114 HSCT recipients were enrolled into the study. At least one infectious complication (IC) was diagnosed in 60 (52.6%) patients aged 0.1-17.7 years, that is, 59.5% with SCID and 49.4% with non-SCID. RESULTS: Among 60 HSCT recipients diagnosed with at least one IC, 188 episodes of infectious complications (EIC) were recorded, that is, 46.8% of BI, 41.5% of VI, and 11.7% of proven/probable IFD. According to PID and HSCT donor type, the incidence of EIC was comparable (P = .679). The localization of infections differed significantly due to PID type (P = .002). After each HSCT donor type, the most common site of infection was GI. Overall, BI caused by Gram-positive strains (59.1%) were prevalent, especially Staphylococcaceae. The multidrug-resistant (MDR) pathogens were diagnosed in 52.3%, especially ESBL + Enterobacteriaceae. The profile of VI was comparable for SCID and non-SCID patients (P = .839). The incidence of IFD was comparable for each PID and HSCT donor type. Survival after infection was 91.5% and was comparable for PID and HSCT donor type. CONCLUSIONS: The rate of patients diagnosed with IC among pediatric PID-HSCT recipients did not depend on PID type, but rather on HSCT donor type. The localization of IC depended on PID and HSCT donor type. Within bacterial infections, predominated Gram-positive strains and the MDR pathogens were responsible for more than half of EIC.

The Successful Sequential Use of Plerixafor and Eltrombopag For Hematopoietic Cell Transplantation in a Child With High-risk Neuroblastoma.

High-dose chemotherapy with autologous hematopoietic stem cell transplantation improves event-free survival in patients with high-risk neuroblastoma. However, in heavily pretreated patients, poor marrow function can be an obstacle in the successful proceeding of therapy. Priming with plerixafor plus filgrastim is an option for effective mobilization and collection of stem cells. In addition, thrombopoietin agonist eltrombopag can improve the outcome of posttransplantation thrombocytopenia and poor graft function in the posttransplant setting. We describe a case of a child with high-risk neuroblastoma, for whom plerixafor and eltrombopag were used as an effective and safe supportive therapy.

Successful Management of Unusual Multiple Gut Colonization With Extremely Drug-resistant Bacteria in an Infant Undergoing Hematopoietic Cell Transplantation.

Enterobacterales represent a serious threat to transplant patients due to their increase frequency of carbapenem resistance and wide spreading. We present a case of an infant with acute lymphoblastic leukemia undergoing hematopoietic stem cell transplantation. Before transplantation an unusual double colonization of the gastrointestinal tract with extremely resistant Escherichia coli and Klebsiella pneumoniae strains producing metallo-beta-lactamase was diagnosed. Respective epidemiologic management was implemented, based on the strict reverse isolation in patient-protective environment, and intensified antimicrobial surveillance. After granulocyte recovery, no extremely drug-resistant strains were found, and no case of isolation and/or transmission of carbapenem-resistant bacteria has been identified in the transplant center during the following 6 months.

The influence of different intensity of treatment on hormonal markers of gonadal function in acute lymphoblastic leukemia survivors.

Anti-cancer treatment in children can deteriorate gonadal function and affect future fertility. We analyzed the hormonal markers of gonadal function in adolescent leukemia survivors, treated in childhood with different levels of aggressiveness. We analyzed hormone levels in 69 adolescents and young adults, leukemia survivors stratified into standard (SR), intermediate (IR), and high (HR) risk groups, and in 80 healthy controls (38 men) at a similar age. We assessed follicular stimulating hormone (FSH), luteinizing hormone (LH), and inhibin B in the whole group, testosterone in males, and E2 and anti-Müllerian hormone (AMH) in females. Males classified into HR group presented, in comparison to control, higher levels of FSH, LH, lower inhibin B, and normal testosterone, whereas in SR and IR group, the hormonal values were comparable to the control. In females, in all risk groups, the levels of FSH, LH, E2, and inhibin B were comparable with the control, but the mean AMH levels were slightly lowered. We did not observe the effect of prophylactic cranial irradiation (12 or 18 Gy) or the time of treatment (before vs. during puberty) on hormone levels. In females, a positive correlation was found between the time interval after the end of treatment and AMH levels. Male leukemia survivors having undergone more intensive chemotherapy show the symptoms of disturbed spermatogenesis and need to be followed-up in the future. Women, irrespective of the risk group, can develop the signs of preterm ovarian insufficiency. They should be informed about the impact of the treatment on gonadal function.

Age-dependent determinants of infectious complications profile in children and adults after hematopoietic cell transplantation: lesson from the nationwide study.

Incidence and outcome of microbiologically documented bacterial/viral infections and invasive fungal disease (IFD) in children and adults after hematopoietic cell transplantation (HCT) were compared in 650 children and 3200 adults in multicenter cross-sectional nationwide study. Infections were diagnosed in 60.8% children and 35.0% adults, including respectively 69.1% and 63.5% allo-HCT, and 33.1% and 20.8% auto-HCT patients. The incidence of bacterial infections was higher in children (36.0% vs 27.6%; p < 0.0001). Infections with Gram-negative bacteria were more frequent than Gram-positives in adults (64.6% vs 44.8%; p < 0.0001). Outcome of bacterial infections was better in children (95.5% vs 91.4%; p = 0.0011). The IFD incidence (25.3% vs 6.3%; p < 0.0001) and outcome (88.0% vs 74.9%; p < 0.0001) were higher in children. The incidence of viral infections was higher in children after allo-HCT (56.3% vs 29.3%; p < 0.0001), and auto-HCT (6.6% vs 0.8%; p < 0.0001). Outcome of viral infections was better in children (98.6% vs 92.3%; p = 0.0096). Infection-related mortality was 7.8% in children and 18.4% in adults (p < 0.0001). No child after auto-HCT died of infection. Adult age, mismatched transplants, acute leukemia, chronic GVHD, CMV reactivation, infection with Gram-negatives, and duration of infection > 21 days were risk factors for death from infection. In conclusion, pediatric patients have 2.9-fold higher incidence and 2.5-fold better outcome of infections than adults after HCT.

Development and current use of in hematopoietic stem cell transplantation in children and adolescents in Poland: Report of the Polish pediatric study group for hematopoietic stem cell transplantation of the Polish society for pediatric oncology and hematology.

The purpose of the survey was to evaluate the development and current use of hematopoietic stem cell transplantation (HSCT) in Poland between 1989-2016. The data for analysis (indication, number of performed HSCT, HSCT type, donor type, and stem cell source, year) have been collected annually using a standardized form. In Poland, between 1989-2016, the number of pediatric transplant beds grew from one to 40 and number and rate of transplants increased annually from 1/year (0.8/10 million) to 186/year (248/10 million). During the analyzed time period 2506 HSCTs were performed, including 1718 (68.6%) allogeneic transplants (allo-HSCT) with142 in 2016 and 788 (31.4%) autologous transplants (auto-HSCT) with 44 in 2016. Among 1718 allo-HSCT, 74% were performed for malignancy (ALL 47.2%, AML 26.2%, MDS 10.8%, CML 8.1%, NHL/HD 6.1%, others 2.5%), and 26% for non-malignant disorders (SAA 41%, congenital immunodeficiencies 35.4%, hereditary bone marrow failure 16%, metabolic disorders 7%). Among 788 auto-HSCTs, 30.8% were done for hematological malignancy (NHL 41.2%, AML 23.9%, HD 17.7%, ALL 15.6%, other 1.5%), while the remaining 69.2% for solid tumors (neuroblastoma 59.8%, Ewing's sarcoma 20.4%, other 19.8%). In Poland, between 1989-2016, the infrastructure indispensable to perform HSCT in every child with indication for this therapeutic procedure was created, and HSCT became an important part of pediatric treatment, especially in pediatric oncology, hematology, and in primary immunodeficiencies.

X-linked TLR7 gene polymorphisms are associated with diverse immunological conditions but not with discoid lupus erythematosus in Polish patients.

INTRODUCTION: Toll-like receptor 7 (TLR7) is an important molecule involved in the development of autoimmunity and the response to different pathogens. Several polymorphisms within the TLR7 gene were previously found to be associated with systemic lupus erythematosus (SLE). However, none of those studies investigated the TLR7 promoter flanking variants rs1634318 and rs1616583. TLR7 gene diversity has not been analyzed with respect to discoid lupus erythematosus (DLE) development, while its role in the human immunological response to fungal infection is not fully known. AIM: To clarify the potential involvement of two novel single-nucleotide polymorphisms (SNPs) located in the TLR7 gene (rs1634318 and rs1616583) in a variety of immune-related conditions, we studied the variability of these loci in patients from a Polish population with SLE and DLE, as well as in immunocompromised patients who were affected by invasive aspergillosis (IA) and those who were not affected. MATERIAL AND METHODS: Real-time polymerase chain reaction was used to genotype SNPs. Statistically significant differences between case and control groups for both allele and genotype frequencies were assessed using the χ2 test with Yates' correction or two-tailed Fisher's exact test. The results were Bonferroni-corrected for multiple comparisons and odds ratios were calculated. RESULTS: Two polymorphisms located in TLR7 might be associated with the development of SLE but not DLE within the Polish population. Moreover, variation of the two investigated SNPs was found to be associated with IA in immunocompromised Polish patients. CONCLUSIONS: In Polish patients, TLR7 promoter flanking gene polymorphisms might be associated with IA and SLE but not DLE.

Outcome of acute lymphoblastic leukemia in children with down syndrome-Polish pediatric leukemia and lymphoma study group report.

Children with Down syndrome (DS) have a 20-fold increased risk of developing leukemia compared with the general population. The aim of the study was to analyze the outcome of patients diagnosed with Down syndrome and acute lymphoblastic leukemia (ALL) in Poland between the years 2003 and 2010. A total of 1848 children were diagnosed with ALL (810 females and 1038 males). Of those, 41 (2.2%) had DS. The children were classified into three risk groups: a standard-risk group-14 patients, an intermediate-risk group-24, a high-risk group-3. All patients were treated according to ALLIC 2002 protocol. The median observation time of all patients was 6.1 years, and in patients with DS 5.3 years. Five-year overall survival (OS) was the same in all patients (86% vs 86%, long-rank test, p = .9). The relapse-free survival (RFS) was calculated as 73% in patients with DS and 81% in patients without DS during a median observation time (long-rank test, p = .3). No statistically significant differences were found in the incidence of nonrelapse mortality between those two groups of patients (p = .72). The study was based on children with ALL and Down syndrome who were treated with an identical therapy schedule as ALL patients without DS, according to risk group. This fact can increase the value of the presented results.

Massively parallel targeted resequencing reveals novel genetic variants associated with aspergillosis in paediatric patients with haematological malignancies.

This study aimed to find novel genetic variants of susceptibility to aspaergillosis in paediatric patients with haematological malignancies. Complete sequences of fifteen genes of human innate immunity (CCL2, CCR2, CD209, CLEC6A, CLEC7A and ten TLR genes) were studied in 40 patients diagnosed with haematological disorders (20 unaffected and 20 affected by aspergillosis). All samples were sequenced with MiSeq (Illumina) and 454 (Roche Diagnostics) technologies. Statistical significance of the differences between studied groups was determined using the two-tailed Fisher's exact test. Sixty variants of potential importance were identified, the vast majority of which are located in non-coding parts of the targeted genes. At the threshold of p < 0.000005, one intergenic (TLR2 rs4585282) and one intronic variant (CLEC6A rs12099687) were found significant between the case and control groups for genotype and allele frequencies, respectively. Rs12099687 in CLEC6A was predicted to constitute an alternative isoform or cryptic splice site, which potentially changes activity of the Dectin-2 protein. Overall, we assume that the two strongest associations reported in this study are expected to be reproducible even in the absence of other evidence, while another twelve associations may be strong enough to justify additional research in larger cohorts.

RNA isolation from bloodstains collected on FTA cards - application in clinical and forensic genetics.

Aim of the study: In recent years, RNA analysis has been increasingly used in clinical and forensic genetics. Nevertheless, a major limitation of RNA-based applications is very low RNA stability in biological material, due to the RNAse activity. This highlights the need for improving the methods of RNA collection and storage. Technological approaches such as FTA Classic Cards (Whatman) could provide a solution for the problem of RNA degradation. However, different methods of RNA isolation from FTA cards could have diverse effects on RNA quantity and quality. The purpose of this research was to analyze the utility of three different methods of RNA isolation from peripheral blood collected on FTA Classic Cards (Whatman). The study also aimed at assessing RNA stability in bloodstains deposited on FTA cards. Material and methods: The study was performed on peripheral bloodstains collected from 59 individuals on FTA Classic Cards (Whatman). RNA was isolated with High Pure RNA Isolation Kit (Roche Diagnostics), Universal RNA/miRNA Purification (EURx) and TRIzol Reagent (Life Technologies). RNA was subjected to quantitative analysis followed by reverse transcription and Real - Time PCR reaction. Results: The study has shown that FTA Classic Cards (Whatman) are useful tools for storing bloodstains at room temperature for RNA analysis. Moreover, the method of RNA extraction employing TRIzol Reagent (Life Technologies) provides the highest efficiency and reproducibility for samples stored for no more than 2 years. Conclusions: The FTA cards are suitable for collecting and storing bloodstains for RNA analysis in clinical and forensic genetics.

Effect of food on selumetinib pharmacokinetics and gastrointestinal tolerability in adolescents with neurofibromatosis type 1-related plexiform neurofibromas.

Background: Selumetinib is approved for the treatment of pediatric patients with neurofibromatosis type 1 (NF1) who have symptomatic, inoperable plexiform neurofibromas (PN) in multiple countries, including the USA (≥ 2 years). Until recently, individuals had to take selumetinib twice daily (BID) in a fasted state. This study evaluated the effect of a low-fat meal on selumetinib PK parameters and gastrointestinal (GI) tolerability in adolescent participants with NF1-PN. Methods: Eligible participants aged ≥ 12 to < 18 years took 25 mg/m2 selumetinib BID with a low-fat meal (T1) for 28 days, followed by a 7-day washout, and then administration in a fasted state (T2) for another 28 days. Primary objectives were to evaluate the effect of a low-fat meal on AUC0-12,ss and GI tolerability after multiple selumetinib doses in T1 versus T2. Key secondary objectives were additional PK parameters and adverse events (AEs). Results: At primary data cut-off, all 24 participants completed T1, and 23 participants completed T2. There were no significant differences in AUC0-12,ss between T1 and T2. In T1 and T2, 29.2% and 33.3% participants, respectively, reported ≥ 1 GI AE. No GI AEs Grade ≥ 3, or serious AEs, or GI AEs resulting in treatment interruptions, discontinuation, or dose reductions were reported in T1 and T2. Conclusions: Dosing selumetinib with a low-fat meal had no clinically relevant impact on selumetinib AUC0-12,ss nor GI tolerability in adolescents with NF1-PN. Trial registration ClinicalTrialsgov ID: NCT05101148.

Cytogenetic findings in Polish patients with suspected Fanconi anemia.

BACKGROUND: The high sensitivity of cells of Fanconi anemia (FA) patients to DNA cross-linking agents (clastogens), such as mitomycin C (MMC), was used as a screening tool in Polish children with clinical suspicion of FA. OBJECTIVES: The aim of the study was to compare chromosome fragility between 3 groups, namely non-FA, possible mosaic FA and FA patients. MATERIAL AND METHODS: The study included 100 children with hematological manifestations and/or congenital defects characteristic of FA, and 100 healthy controls. Blood samples obtained from participants were analyzed using an MMC-induced chromosomal breakage test. RESULTS: Patients with clinical suspicion of FA were divided into 3 subgroups based on the MMC test results, namely FA, possible mosaic FA and non-FA. Thirteen out of 100 patients had a true FA cellular phenotype. The mean value of MMC-induced chromosome breaks/cell for FA patients was higher than for non-FA patients (6.67 ±3.92 compared to 0.23 ±0.18). In addition, the percentage of cells with spontaneous aberrations was more than 9 times higher in FA patients than in non-FA patients. CONCLUSIONS: Our results confirmed that the MMC sensitivity test distinguishes between individuals affected by FA, those with possible somatic mosaicism, and patients with bone marrow failure for other reasons, who were classified as non-FA in the first diagnostic step. However, a definitive differential diagnosis requires follow-up mutation testing and chromosome breakage analysis of skin fibroblasts.

Identification of the genes expression profile associated with the ex vivo resistance to etoposide in childhood acute leukemias.

INTRODUCTION: Drug resistance and the gene expression profiles might discriminate the therapy outcome, and indicate the subgroup of patients with poor prognosis. In this study we analyzed the gene expression profile in correlation with the profile of ex vivo resistance to etoposide in children with acute leukemias. METHODS: The ex vivo drug resistance profile was determined by the MTT cytotoxicity assay performed on leukemic blasts of 56 patients. Gene expression profiles were obtained from the results of hybridization of cRNA to Human Genome U133A 2.0 ologonucleotide arrays. The following analyses were performed: correlation analysis, hierarchical clustering, the assignment of location and function. Verification of data for four selected genes (MNDA, GH1, NUDT21, RHOG) was performed by quantitative real time polymerase chain reaction in the studied population and in an independent group of 54 leukemic patients. RESULTS: Using the permutation Spearman correlation test, a set of 233 probes/209 genes was selected. The global test confirmed the significance of the correlation of gene expression profile and resistance to etoposide (p<0.001). The NUDT21 (nudix, nucleoside diphosphate linked moiety X-type, motif 21) gene showed the strongest correlation with resistance to etoposide (FDR<0.0001%). CONCLUSIONS: Profiling of transcriptome may help in assessing the sensitivity to drugs used in chemotherapy. Resistance to etoposide is possibly associated with a change of expression of a large number of biologically important genes that influence several cellular mechanisms.