Medulloblastomas of the WNT molecular group (MB-WNT) represent the smallest group of MB and account for only 10 % of the total. This molecular group is characterized by a favorable prognosis. Given the aggressive treatment regimens for MB, reducing the intensity of therapy for prognostically favorable tumors seems justified. Purpose of the study – to demonstrate the results of treatment of children with MB-WNT and to determine the impact on survival of various prognostic factors. The study included 85 patients with MB-WNT under the age of 18 who received treatment and were followed up from 1993 to 2022. Median age at diagnosis was 10 years (min – 3, max – 17). All patients had classical MB. Metastatic spread of the tumor at the time of diagnosis was detected in 18 (21.2 %) patients, the presence of a residual tumor according to postoperative magnetic resonance imaging – in 32 (37.7 %). Somatic mutations in the TP53 gene were detected in 10 (7.1 %) patients, in the CTNNB1 gene – in 79 (92.9 %), in the APC gene – in 5 (5.9 %), chromosome 6 monosomy – in 76 (89.4 %) children. At the time of the analysis, 74 (87.1 %) patients were alive, 11 (12.9 %) patients died, a relapse was diagnosed in 6 (7.1 %) patients, of which 5 died from disease progression, 1 patient is alive in the second remission. One patient in long-term remission developed secondary meningioma 20 years after the diagnosis of MB. The 10-year progression-free survival (PFS) was 0.92. 5-year overall survival (OS) was 0.90, 10-year – 0.86. The median OS is 112 months. When analyzing the sample of patients with MB-WNT in our study, PFS and OS were statistically significantly higher in girls without metastatic tumor spread, with total resection of the tumor, stratified into the low-risk group, and in the absence of a somatic mutation in the TP53 gene in the tumor tissue. In multivariate analysis, PFS was influenced by the stage of the disease and the presence of a somatic mutation in the TP53 gene in the tumor tissue; on OS – only the presence of a somatic mutation in the TP53 gene in the tumor tissue.

Introduction. The development of technologies for molecular genetic typing of tumors of the central nervous system (CNS) has significantly increased the specificity of traditional histological and immunohistochemical research methods. As a result, completely new variants of tumors have appeared, as well as improved results of treatment of tumors with a long-term favorable prognosis. Thanks to new biomarkers, among morphologically similar small-cell embryonic CNS tumors, extremely rare tumors have been identified: ETMR (embryonic tumor with multiple rosettes C19MC), CNS NB-FOXR2 (CNS neuroblastoma (NB) with FOXR2-activation), CNS EFT-CIC (tumor of the CNS sarcoma family of sarcoma alteration), CNS HGNET-MN1 (neuroepithelial tumor of the CNS of high grade with MN1 alteration), CNS HGNET-BCOR (neuroepithelial tumor of the CNS of high grade with BCOR alteration).The aim of the study was to assess the historical prerequisites for the emergence of a new rare nosological form “CNS NB with FOXR2- activation”, as well as presentation of own results of diagnostics and treatment of children with this tumor.Materials and methods. The results of diagnosis and treatment of 7 patients with CNS NB with FOXR2-activation were studied. Tumor identification was carried out using a new DNA methylation technique for CNS tumor profiles using the Heidelberg (Germany) brain tumor classifier (www.molecularneuropathology.org), which has recently become available in Russia.Results and discussion. Based on a review of international experience, the evolution of the appearance in the classification of CNS tumors, as well as the clinical and molecular features of CNS neuroblastoma with FOXR2-activation are presented. The authors present their own results of diagnostics and treatment of 7 patients with a rare tumor CNS neuroblastoma with FOXR2-activation.Conclusion. Biomarkers have been proposed for the differential diagnosis of small-cell PNET-like tumors of the CNS in children. Due to the molecular identification of this tumor in children, it became clear that such patients, provided that the treatment protocol is adequately followed, have quite satisfactory long-term survival results.

Diamond–Blackfen Anemia (DBA) is a rare, clinically and genetically heterogeneous disorder from the group of congenital syndromes of bone marrow failure. The purpose of this work is to identify the main medical-frequency characteristics of DBA (incidence, prevalence, mortality, cartographic analysis) in children in the Russian Federation during the observation period 2011–2016. The study was approved by the Independent Ethics Committee of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology. The Russian register of DBA patients, which had been developed and maintained since 2012 year by NMITS DGOI, was used to obtained epidemiological data and their analysis. At the end of 2018 year 141 patients from 137 families were included in the register. The average annual incidence rate of children with DBA for the Russian Federation was 0.63 ± 0.034, the average annual prevalence rate – 5.75 ± 0.87 per 100 thousand newborns born alive; mortality rate – 2.12%; the cartographic method of research showed that the largest number of patients was registered in the Central Federal District of the country, which is explained by the high population living in this district.

SHH group of medulloblastoma is a heterogeneous tumor cohort. The neoplasms differ by biological characteristics as well as clinical features and prognosis of the disease. Purpose of the study is the analysis of clinical, molecular and genetic features for prognosis defining in patients with SHH group medulloblastoma. 28 patients with SHH group medulloblastomas were included in the study. The MB molecular group verification was performed in parallel by Nanostring gene expression profiling and immunohistochemical assessment of tumor samples. The detection of TP53 gene mutations was carried out with Sanger sequencing. The prognostic impact of the clinical, molecular and genetic factors of the disease was analyzed by calculating 5-years event-free survival (EFS). The median of follow up time achieved 38.9 months. All patients harboring the TP53 mutation (n = 3) had dismal outcome (two patients died from the progression of the disease, one patient has secondary tumor). Children from older age group (> 3 years) had more adverse events comparing to younger children (< 3 years): EFS 49.2 ± 31.3% vs. 78.8 ± 13.9%. The relapse of the disease occurred in 7 patients (25%). Notably, that in younger children the second line treatment was effective. The presence of TP53 mutations as well as age above 3 years are associated with poor prognosis in SHH group medulloblastomas. The novel molecular and genetics markers are needed for precise prognosis defining.

The purpose of the current work was the estimation of prognostic significance of cytogenetic and molecular markers, assessed by multiplex ligation-dependent probe amplification (MLPA) in 142 cases of pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) patients. Good-risk genetic (GEN-GR) group consisted of 114 patients carrying either ETV6-RUNX1 or high hyperdiploidy together with normal copy-number status for all 8 genes (IKZF1, PAX5, ETV6, RB1, BTG1, EBF1, CDKN2A/2B and PAR1) or isolated deletions affecting ETV6/ PAX5/BTG1 and ETV6 deletions with a single additional deletion of BTG1/PAX5/CDKN2A/2B. All other patients (n = 28) were classified to genetic poor risk (GEN-PR) group. GEN-PR features were older age (p = 0.015), stratification to high-risk group of ALL-MB 2008 protocol (p = 0.001), higher initial WBC (p = 0.008), M3 marrow status on day 15 (p = 0.002) and lack of remission on day 36 (p = 0.039). GEN-PR patients had statistically significant lower event-free survival (EFS) (0.59 ± 0.11 vs 0.88 ± 0.03; p = 0.0008), overall survival (OS) (0.63 ± 0.15 vs 0.93 ± 0.02; p = 0.0050) and higher cumulative incidence of relapse (CIR) (0.38 ± 0.12 и 0.06 ± 0.02; p < 0.0001) in comparison to GEN-GR patients. Genetic risk group stratification retained its negative prognostic value in multivariate analysis affecting EFS (hazard ratio (HR) – 2.659; 95 % CI 1.047–6.755; p = 0.040) and CIR (HR – 3.864; 95 % CI 1.226–12.183; p = 0.021), nut did not influenced to OS (HR – 1.479; 95 % CI 0.356–6.139; p = 0.590). There was no prognostic significance of genetic risk group classifier in the “B-other ALL” group. Majority of unfavorable events (9 out of 10) and relapse (8 out of 9) in GEN-PR patients were revealed in case of IKZF1 deletion co-occurrence. Moreover all 15 patients carrying IKZF1 deletions were stratified to GEN-PR group. So when we added IKZF1 deletion as extra variable in the multivariate analysis genetic risk group classification lost its prognostic significance on EFS (HR – 0.696; 95 % CI 0.086–5.636; p = 0,735), and CIR (HR – 0.511; 95 % CI 0.053–4.924; p = 0.561), while IKZF1 deletion remained its prognostic value both to risk of unfavorable event (HR – 4.292; 95 % CI 1.521–12.911; p = 0.006) and risk of relapse (HR – 9.163; 95 % CI 3.131–26.815; p < 0.001). Thus, combination of cytogenetic risk group and MLPA markers did not bring any advantage over detection of isolated IKZF1 deletion for the estimation of prognosis in pediatric BCP-ALL.

One of the main risk-factors of acute lymphoblastic leukemia (ALL) is age. The most favorable age group is children from 2 to 9 years old, and the adolescents and young adults have the worst prognosis. Treatment of ALL at adolescents and young adults is a unique problem of modern hematology now. This work presents the analysis of 368 cases of patients with primary ALL 15–18 years old, which were registered in the database of Russian-Belarussian group from April 2002 to November 2014. The aim of the analysis was the estimation of effectiveness of different generations of protocol for adolescents and prognostic significance of different factors to reveal the ways of future therapy optimizing in this age group. Event-free survival of adolescents 15–18 years old according our study was 56 ± 5 % in ALL-MB-2002 study and 57 ± 6 % in ALL-MB-2008 study. We did not received any differences in survival based on immunophenotype of blast cells. But the risk group analysis showed the worst results at patients with ALL from pre-B-precursor cells of high risk. No difference was revealed according the gender. One of the general problems remains high toxicity of therapy at patients of this age group. Treatment related mortality (TRM) was 13.2 and 12 % at ALL-MB-2002 and ALL-MB-2008 accordingly. Main cause of deaths remains infection.

AIMTo determine predictors for decision-making on a differential approach to choosing glucocorticosteroids (GCS) for children and adolescents with acute lymphoblastic leukemia (ALL).SUBJECTS AND METHODSThe analysis covered 1064 primary patients aged to 1 to 18 years with ALL who had been registered at the clinics of Russia and Belorussia in April 2002 to November 2006. Before induction therapy, the patients were randomized into a dexamethasone (DEXA) 6 mg/m2 group (n=539) and a methylprednisolone (MePRED) 60 mg/m2 one (n=525).RESULTSThe entire group showed no statistically significant differences in survival rates between the patients receiving DEXA or MePRED. However, an analysis of age groups revealed the benefits of DEXA in children younger than 14 years (the event-free survival (EFS) was 76±2 and 71±2%, respectively (p=0.048); the overall survival (OS) was 81±2 and 77±2%, respectively (p=0.046); therapy-induced mortality was 6.4% (DEXA) andl 1.1% (MePRED) (p=0.01 4); the rate of isolated extramedullary relapses was 1.5% (DEXA) and 4.4% (MePRED) (p=0.009). At the same time, EFS and OS in 14-to-18-year-old adolescents were statistically significantly higher than in those who used MePRED (EFS, 65±6 and 52±6%, respectively (p=0.087); OS, 72±6 and 61±6%, respectively; (p=0.l 7).CONCLUSIONThe findings suggest that it is possible that the choice of a GCS for ALL therapy must be also based on a patient's age. There is a need for further studies of this matter in prospective randomized multicenter trials in children and adolescents.