Clinical impact of genomic analysis in children with B-acute lymphoblastic leukemia: A pilot study in Slovakia.

Acute lymphoblastic leukemia (ALL) belongs to a genetically heterogeneous disease associated with a wide range of chromosomal and molecular changes. Determining these changes at the time of diagnosis can help the therapeutic decision, and contributes to the prediction of patients' clinical outcomes. A part of B-ALL (B-other) lacks cytogenetic abnormalities with clinical relevance for prognosis. Our first goal was to retrospectively review genetic results of patients from 2013-2017 and identify number of B-other patients in Slovak population. The second goal was to implement single nucleotide polymorphism (SNP) array analysis to improve the diagnosis and risk stratification. In this study we reviewed 133 B-ALL patients. We found that nearly 40% of them (52 cases) belonged to the B-other ALL group. Eighteen B-other ALL patients were subjected to the analysis using SNP-array. Overall, we identified 126 cytogenomic changes and in 4 patients the SNP array revealed clinically relevant markers of adverse prognosis and high relapse risk. Integrating identified genetic changes into clinical practice can bring improvement of prognosis assessment for children with ALL in Slovakia.

Diagnosis and treatment of juvenile myelomonocytic leukemia in Slovak Republic: novel approaches.

Juvenile myelomonocytic leukemia (JMML) is a rare, aggressive clonal myeloproliferative disorder of infancy and early childhood caused by oncogenic mutations in genes involved in the Ras pathway. Long-term survival has only been achieved with hematopoietic stem cell transplantation (HSCT), being able to cure more than 50% patients. To manage the disease before HSCT remains an important issue with constant searching for optimal treatment modalities. According to several retrospective analyses, azacitidine (AZA) induced clinical and molecular responses in patients with relapsed JMML pre-transplant and post-transplant, suggesting its use as a promising "bridging" therapy before HSCT. In this paper we report our first consecutive cohort of patients with JMML treated at our institution as well as our experience with the diagnosis, novel treatment and management of these patients before the HSCT. We present 6 patients with JMML, harboring different somatic mutations (PTPN11 and NRAS), with distinct clinical features; 3 of them had been treated with AZA 75 mg/m2 i.v. on days 1 to 7 of a 28-day cycle before the HSCT. Response to therapy was evaluated after each cycle in accordance with the International response criteria. One patient had a progression of splenomegaly during the treatment and after three cycles he was urgently transplanted. At the present, he is remaining in complete remission 3 years after HSCT. Two patients showed impressive response following the first cycle of the therapy with a regression of splenomegaly and monocyte count, normalized leukocytes, platelets and absent blasts in peripheral blood. The treatment was well tolerated with no adverse effect recorded. The clinical activity and favorable toxicity of AZA in JMML provide a rationale for its use as a "bridging" therapy before HSCT. Prospective trials with accompanying translational studies are required to provide further information regarding individual factors that may direct the most appropriate choice of pretransplantation therapy.

Pilot Study of the Occurrence of Somatic Mutations in Ciliary Signalling Pathways as a Contribution Factor to Autosomal Dominant Polycystic Kidney Development.

Autosomal-dominant polycystic kidney disease (ADPKD) is an inherited disease that results in multiple kidney cysts, and it is a common cause of end-stage renal disease. Recent studies have shown that disease progression can be slowed by simultaneous disruption of the primary cilium and polycystins. The exact genetic mechanism of this process is still unknown. The aim of the present study was to characterize the mutation profile of ciliary signalling pathways in the renal epithelial cells of ADPKD patients. In our study, we performed an analysis of 110 genes encoding the components of Sonic Hedgehog, Hippo, Notch, Wnt and planar cell polarity signalling (PCP) by targeted next-generation sequencing. We analysed 10 formalin-fixed, paraffinembedded (FFPE) tissue samples of patients with ADPKD. We identified a unique mutation profile in each of the analysed ADPKD samples, which was characterized by the presence of pathogenic variants in eight to 11 genes involved in different signalling pathways. Despite the significant genetic heterogeneity of ADPKD, we detected five genes whose genetic variants affected most ADPKD samples. The pathogenic variants in NCOR2 and LRP2 genes were present in all analysed samples of ADPKD. In addition, eight out of 10 samples showed a pathogenic variant in the MAML2 and FAT4 genes, and six out of 10 samples in the CELSR1 gene. In our study, we identified the signalling molecules that may contribute to the cystogenesis and may represent potential targets for the development of new ADPKD treatments.