Infrared Spectroscopy as a Potential Diagnostic Tool for Medulloblastoma.

INTRODUCTION: Medulloblastoma (MB) is the most common malignant tumor of the central nervous system in childhood. FTIR spectroscopy provides a holistic view of the chemical composition of biological samples, including the detection of molecules such as nucleic acids, proteins, and lipids. This study evaluated the applicability of FTIR spectroscopy as a potential diagnostic tool for MB. MATERIALS AND METHODS: FTIR spectra of MB samples from 40 children (boys/girls: 31/9; age: median 7.8 years, range 1.5-21.5 years) treated in the Oncology Department of the Children's Memorial Health Institute in Warsaw between 2010 and 2019 were analyzed. The control group consisted of normal brain tissue taken from four children diagnosed with causes other than cancer. Formalin-fixed and paraffin-embedded tissues were sectioned and used for FTIR spectroscopic analysis. The sections were examined in the mid-infrared range (800-3500 cm-1) by ATR-FTIR. Spectra were analysed using a combination of principal component analysis, hierarchical cluster analysis, and absorbance dynamics. RESULTS: FTIR spectra in MB were significantly different from those of normal brain tissue. The most significant differences related to the range of nucleic acids and proteins in the region 800-1800 cm-1. Some major differences were also revealed in the quantification of protein conformations (α-helices, ß-sheets, and others) in the amide I band, as well as in the absorbance dynamics in the 1714-1716 cm-1 range (nucleic acids). It was not, however, possible to clearly distinguish between the various histological subtypes of MB using FTIR spectroscopy. CONCLUSIONS: MB and normal brain tissue can be distinguished from one another to some extent using FTIR spectroscopy. As a result, it may be used as a further tool to hasten and enhance histological diagnosis.

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.

Monitoring of treatment with L-asparaginase in children with acute lymphoblastic leukaemia, with a focus on silent inactivation and its influence on the treatment outcome.

Introduction: The aim of the study was to analyse the frequency of silent inactivation and allergic reaction to asparaginase (ASP) and its impact on treatment results in patients with lymphoblastic leukaemia. Material and methods: Seventy patients with acute lymphoblastic leukaemia treated with ASP were enrolled in the study. Asparaginase activity was monitored. The patients were switched to another ASP formulation after allergy or inactivation. The treatment results were analysed. Results: Silent inactivation of native E. coli ASP was diagnosed in 5 patients (7%) and allergy in 34 patients (49%), and these patients were switched to pegylated ASP (PEG-ASP). Silent inactivation of PEG-ASP occurred in 8 patients (23%) and allergy in 6 patients (17%). Eight children continued therapy with Erwinase, and 4 did not switch to Erwinase after inactivation of PEG-ASP. Allergy to Erwinase occurred in 2 patients (22%); there was no inactivation. No significant differences in outcome were found between the groups of patients with and without allergy or silent inactivation of ASP. Due to regular monitoring and switching to other ASP preparations after allergy or silent inactivation, therapeutic activity was ensured in almost all patients. Conclusions: Monitoring of ASP activity is crucial to recognize silent inactivation and to guarantee treatment effectiveness by switching to other ASP preparations.

Nodular lymphocyte predominant Hodgkin lymphoma: Experience of Polish Pediatric Leukemia/Lymphoma Study Group.

Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL) is a rare clinical entity. To investigate NLPHL clinical course and treatment a survey was performed within Polish Pediatric Leukaemia/Lymphoma Study Group (PPLLSG) participating centers. A questionnaire was sent to all participating centers and analysis of clinical data was performed. From 2010 to 2019, 19 pediatric patients with confirmed NLPHL were registered in Poland. Median age of patients was 12.2 (5.5 - 17.8) years. NLPHL occurred mainly in males (n = 17). Most of the patients (n = 16) had early stage disease - Stage I (n = 6) and stage II (n = 10). Four of the six patients with stage I disease (I A, n = 5; I B, n = 1) underwent complete primary resection. One of these relapsed and was treated with CVP (cyclophosphamide, vinblastine, prednisone) chemotherapy. Two other patients who were not resected completely received CVP chemotherapy and no relapses were observed. Thirteen patients presented with unresectable disease. Of these, eight received three CVP chemotherapy cycles, and five were treated with other chemotherapy regimens. Three relapses were observed and these patients were further treated with chemotherapy and rituximab. One patient underwent autologous stem cell transplantation (auto-SCT). All patients remain alive. Five-year progression-free survival and overall survival for the entire group of patients was 81.6% and 100%, respectively. NLPHL treatment results are consistent with results noted in other countries. Early stage patients have very good outcomes with surgery and observation or low intensity chemotherapy, but this approach may be insufficient in advanced disease.

A Preliminary Study of FTIR Spectroscopy as a Potential Non-Invasive Screening Tool for Pediatric Precursor B Lymphoblastic Leukemia.

Early detection of the most common pediatric neoplasm, B-cell precursor lymphoblastic leukemia (BCP-ALL), is challenging and requires invasive bone marrow biopsies. The purpose of this study was to establish new biomarkers for early screening to detect pediatric leukemia. In this small cohort study, Fourier transform infrared (FTIR) spectra were obtained from blood sera of 10 patients with BCP-ALL and were compared with the control samples from 10 children with some conditions other than neoplasm. Using various analytical approaches, including a new physical model, some significant differences were observable. The most important include: the different peak area ratio 2965/1645 cm-1 (p = 0.002); the lower average percentage of both ß-sheet and ß-turn protein structures in the sera of BCP-ALL patients (p = 0.03); an AdaBoost-based predictive model for classifying healthy vs. BCP-ALL patients with 85% accuracy; and the phase shift of the first derivative in the spectral range 1050-1042 cm-1 correlating with white blood cell (WBC) and blast cell count in BCP-ALL patients contrary to the samples obtained from healthy controls. Although verification in larger groups of patients will be necessary, these promising results suggest that FTIR spectroscopy may have future potential for the early screening of BCP-ALL.

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.

Body Mass Index (BMI) and Infectious/Febrile Episodes in Children with Intermediate Risk Acute Lymphoblastic Leukemia (IR ALL).

The incidence of treatment related mortality in children with acute lymphoblastic leukemia (ALL) is reported to be between 2% and 4% with infections being the leading cause. AIM: To establish a relationship between body mass index at diagnosis (BMI 0), after protocol I therapy completion (BMI I) and the incidence rate ratio (IRR) of infectious/febrile episodes in children with ALL intermediate risk. METHODS: Thirty one consecutive patients (2-18 years old, with a male to female ratio of 19/12) with newly diagnosed ALL that were treated uniformly according to ALL IC 2009 protocol were included in this analysis. RESULTS: A BMI decrease of at least 5% during protocol I therapy and BMI 1 under 15th percentile score corresponds significantly with higher IRR (with P-values 0.04 and 0.006 respectively) during the whole intensive therapy. CONCLUSION: Some relationships between BMI reduction and higher IRR in ALL patients were found, but their significance is limited by the size of the group analyzed.

Epidemiology and outcome of invasive fungal disease in children after hematopoietic cell transplantation or treated for malignancy: Impact of national programme of antifungal prophylaxis.

The objective of the study was the analysis of incidence and outcome of invasive fungal disease (IFD) in children treated for malignancy (PHO, paediatric hematology-oncology) or undergoing hematopoietic cell transplantation (HCT) over a period of six consecutive years in nationwide study. A total number of 5628 patients with newly diagnosed malignancies and 971 patients after HCT (741 allo-HCT and 230 auto-HCT) were screened for infectious complications in biennial reports. IFD incidence was lower among PHO patients: 8.8% vs 21.2% (P < .0001) and survival from IFD was better: 94.2% vs 84.1% (P < .0001). Auto-HCT patients had lower incidence (10.9% vs 24.4%) and lower mortality than allo-HCT patients. Introduction of national antifungal prophylaxis programme in HCT and acute leukaemia patients decreased incidence of IFD in HCT (from 23.1% to 13.4%) and AML on conventional chemotherapy (from 36% to 23%) but not in ALL patients during chemotherapy. In multivariate analysis, the incidence of IFD was higher in patients after HCT, diagnosed for ALL, AML or NHL, and in patients > 10 years old. Factors contributing to death with infection were as follows: undergoing HCT, diagnosis of acute leukaemia (ALL or AML) and duration of treatment of infection > 21 days. In conclusion, the incidence of IFD in allo-HCT and in AML patients on chemotherapy has decreased after introduction of national programme of antifungal prophylaxis, while the incidence of IFD in ALL patients on chemotherapy did not change significantly. The outcome of IFD both in PHO and HCT patients has largely improved in comparison with historical international data.

Predicting Ewing Sarcoma Treatment Outcome Using Infrared Spectroscopy and Machine Learning.

BACKGROUND: Improved outcome prediction is vital for the delivery of risk-adjusted, appropriate and effective care to paediatric patients with Ewing sarcoma-the second most common paediatric malignant bone tumour. Fourier transform infrared (FTIR) spectroscopy of tissues allows the bulk biochemical content of a biological sample to be probed and makes possible the study and diagnosis of disease. METHODS: In this retrospective study, FTIR spectra of sections of biopsy-obtained bone tissue were recorded. Twenty-seven patients (between 5 and 20 years of age) with newly diagnosed Ewing sarcoma of bone were included in this study. The prognostic value of FTIR spectra obtained from Ewing sarcoma (ES) tumours before and after neoadjuvant chemotherapy were analysed in combination with various data-reduction and machine learning approaches. RESULTS: Random forest and linear discriminant analysis supervised learning models were able to correctly predict patient mortality in 92% of cases using leave-one-out cross-validation. The best performing model for predicting patient relapse was a linear Support Vector Machine trained on the observed spectral changes as a result of chemotherapy treatment, which achieved 92% accuracy. CONCLUSION: FTIR spectra of tumour biopsy samples may predict treatment outcome in paediatric Ewing sarcoma patients with greater than 92% accuracy.

Long-term survival of a child with refractory anaplastic large cell lymphoma following therapy with an antisense oligonucleotide, topotecan, and vinblastine.

Anaplastic large cell lymphoma includes a subset of highly aggressive tumours and has a relapse rate of 30% at 2 years. Relapsed patients often have poor clinical outcome. The use of antisense oligonucleotides to down-regulate Bcl-2 protein can reverse chemotherapy resistance. The authors describe an 11-year-old boy with recurrent anaplastic large cell lymphoma who had received double high-dose chemotherapy followed by autologous haematopoietic stem-cell transplantation, had refractory disease and then had achieved long-term remission with the use of an antisense oligonucleotides in combination with vinblastine and topotecan.

Ovarian function in female survivors after multimodal Ewing sarcoma therapy.

BACKGROUND: With advances in cancer care, more young women with Ewing sarcoma (ES) survive after treatment. Thus, we sought to analyze the ovarian function in prepubertal, pubertal and postpubertal females and young women receiving multimodal therapy for ES, and to identify patients at risk of infertility on whom fertility preservation would be indicated. PROCEDURES: Twenty-seven female survivors of ES were included in this retrospective multiinstitutional study. Patients were classified into four groups according to the treatment received: chemotherapy (CHT) without pelvic radiation (pRT), chemotherapy and pRT, CHT and autologous hematopoietic cell stem rescue (aHSCT) without pRT, and CHT + pRT + aHSCT. The ovarian function and fertility outcomes were analyzed. RESULTS: At a median follow-up of 5.7 years from diagnosis, and at median age at follow-up of 16.3 years, 67% of the survivors had premature ovarian insufficiency, including all patients receiving pelvic RT and 87.5% of patients who underwent aHSCT, independent of chemoprotection. Thirty-seven percent of patients had a clinical syndrome of premature menopause. The relative risk (RR) of premature ovarian insufficiency of a survivor was 3.9 (p 0.03) for pRT, and 2.4 (p 0.07) for aHSCT. On multivariate analysis, radiation therapy was a significant predictor of higher risk of premature ovarian insufficiency over chemotherapy alone. CONCLUSIONS: A large proportion of women receiving multimodal therapy for ES develop premature ovarian insufficiency. Patients and guardians should be informed about the reproductive potential and strategies for preservation of ovarian function should be considered individually. Pediatr Blood Cancer 2015;62:341-345. © 2014 Wiley Periodicals, Inc.

Validation of a multi-modal treatment protocol for Ewing sarcoma--a report from the polish pediatric oncology group.

BACKGROUND: Ewing sarcoma (ES) is the second most common paediatric malignant bone tumor. Advances in multi-disciplinary care have resulted in significant improvement in cure rates over the last decades. However, the generalization of those results in countries traditionally excluded from large cooperative trials has yet to be demonstrated. We report the results of modern multi-disciplinary care for patients with ES in Poland. PROCEDURES: One hundred and thirty-two patients with ES were treated using modern multi-modal therapy during the period 2000-2009. Overall survival was estimated by Kaplan-Meier methods and compared using long-rank test and Cox models. Factors predictive of outcome in our setting were analyzed to identify distinct risk groups that could help identify areas for improvement. RESULTS: The median age at the time of diagnosis was 12.3 years. With a median follow-up of 5.0 years, the 5-year event-free survival (EFS) and OS estimates for localized disease were 54.88% and 68.29%, respectively. For patients with metastatic disease, 5-year EFS and OS estimates were 36% and 42%, respectively. There was no correlation between age and stage or site. Patients with localized, non-pelvic disease had better outcome than patients with axial tumors (71% vs. 44%, respectively, P = 0.00073). Treatment failure was associated with stage, pelvic primary, poor histological response, and type of local control. CONCLUSIONS: Successful treatment of ES requires optimal systemic and local therapy. We were able to replicate the results of modern multi-modal protocols. Validation of current treatment protocols in countries with more limited cancer treatment resources is required.

Pre-Exposure Prophylaxis and Treatment with Tixagevimab/Cilgavimab for COVID-19 among Immunocompromised Pediatric Patients.

Background: Patients treated with hemato-oncological malignancies (HO) or undergoing cellular therapies such as hematopoietic stem cell transplantation (HSCT) or chimeric antigen receptor T cells (CAR-T) were significantly affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the success of SARS-CoV-2 vaccination, immunocompromised patients remain at increased risk for severe coronavirus disease (COVID-19), rendering this group of population a high priority for additional prevention and treatment options. Tixagevimab and Cilgavimab (TIXA/CILGA, AZD7442, Evusheld®) is a combination of two fully human, long-acting monoclonal antibodies. TIXA/CILGA have been approved as pre-exposure prophylaxis and treatment in patients at risk of severe disease with impaired vaccine response. Our objective was to describe the efficacy and safety among immunocompromised pediatric patients. Methods: This was an observational multicenter cohort study of immunocompromised pediatric patients receiving TIXA/CILGA conducted at nine Polish centers of Pediatric Oncology, Hematology and Bone Marrow Transplantation. We analyzed patients in two groups; those treated with HO and those undergoing cellular therapies: HSCT or CAR-T cells. In addition, two other cohorts were identified: patients given TIXA/CILGA as pre-exposure prophylactic and therapeutic intervention. Results: A total of 78 patients were evaluated during the study period: 69 (88.5%) received TIXA/CILGA as pre-exposure prophylaxis and 9 (11.5%) as a treatment strategy. A total of 52 (66.6%) patients were treated with standard chemotherapy at HO departments; 21 (27%) underwent HSCT, and 5 (6.4%) received CAR-T cell therapy. All children with COVID-19 receiving TIXA/CILGA presented a mild degree of severity. The most common clinical manifestations were fever, cough and coryza. At least one adverse event (AE) was reported in two (3.8%) patients excluding standard injection site reactions. Reported AEs were mild or moderate in intensity. One child reported mild myalgia and one reported moderate bone pain and weakness. Conclusions: In our observational multicenter cohort study, we explored the use of TIXA/CILGA as pre-exposure prophylaxis and treatment for COVID-19 among immunocompromised pediatric patients. While our findings suggest a potential benefit in preventing and managing COVID-19 in this vulnerable population, it is important to note the study's non-comparative design. Our results highlight the need for well-designed clinical trials to confirm these observations and further assess the efficacy and safety of TIXA/CILGA in immunocompromised children.

Treatment Outcomes of Adolescents Compared to Younger Pediatric Patients with Acute Myeloid Leukemia: Do They Need a Special Approach?

BACKGROUND: The reports of studies that compare the survival of adolescents and young adults with younger children with acute myeloid leukemia (AML) are contradictory. PATIENTS AND METHODS: We retrospectively analyzed 220 AML patients aged 0-18 years treated in pediatric oncologic centers in Poland from 2015 to 2022. The evaluated group included 31 infants (below 1 year), 91 younger children (1-9.9 years), 59 older children (10-14.9 years), and 39 adolescents (15-18 years). RESULTS: A 5-year overall survival for adolescents was not significantly inferior compared to younger and older children (74.3 ± 7.6% vs. 80.5 ± 4.4% vs. 77.9 ± 5.1, p = 0.243). However, relapse-free survival was lower in adolescents compared to younger children (76.5 ± 7.8% vs. 65.7 ± 9.0%, p = 0.049), and treatment-related mortality tended to be higher (10.3% vs. 4.4%, p = 0.569). In the univariate analysis, high-risk genetics [HR, 2.0 (95% CI 1.1-3.6; p = 0.014)] and a leukocyte count at diagnosis above 100,000/µL [HR, 2.4 (95% CI 1.3-4.6; p = 0.004)] were found to be unfavorable prognostic factors for survival. CONCLUSIONS: Although we have not found that age over 15 years is an unfavorable factor for overall survival, the optimal approach to therapy in adolescents, as in other age groups, is to adjust the intensity of therapy to individual genetic risk and introduce targeted therapies when indicated.

Vincristine, irinotecan, and temozolomide in patients with relapsed and refractory Ewing sarcoma.

BACKGROUND: Patients with metastatic, progressive or recurrent Ewing sarcoma (ES) have a dismal outcome. The combination of irinotecan and temozolomide has been proposed as an effective salvage regimen for some pediatric malignancies. Thus, we sought to evaluate this combination with vincristine for patients with relapsed and refractory ES. MATERIALS AND METHODS: Twenty-two patients with relapsed or refractory ES were treated with the combination of vincristine (1.5 mg/m(2) i.v. day 1), irinotecan (50 mg/m(2) /day i.v. days 1-5) and temozolomide (125 mg/m(2) /day p.o. days 1-5) (VIT) during the period 2008-2012. All toxicities were documented. RESULTS: A total of 91 cycles (median 4.1 cycles/patient) were administered. A complete response (CR) was achieved in five patients, partial response (PR) in seven patients, stable disease (SD) in three patients, and progression disease (PD) in seven patients, with an overall response rate of 68.1%. Median time to progression was 3.0 months (range 1.1-37.1 months). Five patients (22.7%) are alive with no evidence of disease with a median follow-up of 10.3 months (range 2.1-46.5); four of them received consolidation with high-dose chemotherapy and autologous hematopoietic stem cell transplant after responding to VIT. Outcome was better for patients with relapsed ES compared with patients who progressed to initial therapy (estimated 2 year overall survival 36.4% vs. 0%, respectively). There were no significant toxicities. CONCLUSIONS: The shorter, 5-day VIT regimen is an active and well-tolerated regimen in refractory ES. This combination deserves further investigation in the upfront management of patients with metastatic disease.

The BCL-2 protein in precursor B acute lymphoblastic leukemia in children.

The BCL-2 protein plays an important role in controlling apoptosis. Disorders of this process can lead to the emergence and development of acute lymphoblastic leukemia (ALL) and can determine the resistance of leukemic cells to chemotherapy. The levels of BCL-2 mRNA were determined in 20 children with pre-B ALL using RT-polymerase chain reaction and the percentage of BCL-2+ cells in 51 patients using flow cytofluorometry. Similar levels of BCL-2 mRNA (P=0.18) with a higher percentage of cells BCL-2+ (P=0.04) were shown in the bone marrow of patients with pre-B ALL compared to normal peripheral blood mononuclear cells. We could not find any connection between the level of BCL-2 mRNA or the percentage of BCL-2+ cells and selected clinical features. A high percentage of BCL-2+ cells and high levels of BCL-2 mRNA did not affect the 5-year overall survival probability nor the 5-year relapse-free survival probability. These results may indicate a high activity of mechanisms promoting the development of the final form of the BCL-2 protein from mRNA in leukemic cells. A high BCL-2 level does not affect the clinical course or worsen the prognosis in children with ALL.

Gemtuzumab ozogamicin for relapsed or primary refractory acute myeloid leukemia in children-the Polish Pediatric Leukemia and Lymphoma Study Group experience.

Background: Gemtuzumab ozogamicin (GO), one of the first targeted drugs used in oncology, consists of an anti-cluster of differentiation 33 (CD33) monoclonal antibody bound to a derivative of cytotoxic calicheamicin. After the drug withdrawn in 2010 due to a significantly higher rate of early deaths, GO regained approval in 2017 for the treatment of newly diagnosed, refractory, or relapsed acute myeloid leukemia (AML) in adults and children over 15 years of age. The objective of the study was a retrospective analysis of clinical characteristics, treatment outcomes, and GO toxicity profile in children with primary refractory or relapsed (R/R) AML treated in Poland from 2008 to 2022. Methods: Data were collected through the Polish Registry of Acute Myeloid Leukemia. From January 2008 to December 2022, 35 children with R/R AML were treated with GO in seven centers of the Polish Pediatric Leukemia and Lymphoma Study Group. Results: Most of the children (30 of 35) received only one GO cycle in combination with various chemotherapy cycles (IDA-FLA, DOXO-FLA, FLA, FLAG, and others). Eighteen children (51%) achieved complete remission (CR), 14 did not respond to treatment, and three progressed. GO therapy was followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT) in 18 children in CR. The 5-year overall survival (OS) after GO therapy was 37.1% ± 8.7% for the total cohort. There was a trend toward a superior outcome in patients with strong expression of CD33 expression (over 50% positive cells) compared with that in patients with lower expression of CD33 (OS, 41.2% ± 11.9% versus 27.8% ± 13.2%; p = 0.5; 5-year event-free survival, 35.4% ± 11.6% versus 25.7% ± 12.3%; p = 0.5, respectively). Children under 15 years have better outcome (OS, 34.9% ± 10.4% versus 30% ± 14.5%, p = 0.3). The most common adverse events were bone marrow aplasia, fever of unknown origin, infections, and elevated liver enzyme elevation. Sinusoidal obstruction syndrome occurred in two children. Conclusions: The use of GO in severely pretreated children, including those under 15 years of age, with previous failure of AML treatment is a feasible and effective bridging therapy to allo-HSCT with an acceptable toxicity profile.

Characteristics and Outcome of FLT3-ITD-Positive Pediatric Acute Myeloid Leukemia-Experience of Polish Pediatric Leukemia and Lymphoma Study Group from 2005 to 2022.

BACKGROUND: The FMS-like tyrosine kinase 3 (FLT3) gene mutated in 10-15% of pediatric acute myeloid leukemia (AML) is associated with an inferior outcome. The aim of the study was to analyze the outcome and characteristics of FLT3-ITD-positive pediatric AML. METHODS: We retrospectively analyzed the nationwide pediatric AML database from between 2005 and 2022. FLT3-ITD was found in 54/497 (10.7%) patients with available analysis. Three consecutive treatment protocols were used (AML-BFM 2004 Interim, AML-BFM 2012 Registry, AML-BFM 2019 recommendations). RESULTS: Probabilities of 5-year overall (OS), event-free (EFS) and relapse-free survival were significantly lower in the FLT3-ITD-positive patients compared to FLT3-ITD-negative (0.54 vs. 0.71, p = 0.041; 0.36 vs. 0.59, p = 0.0004; 0.47 vs. 0.70, p = 0.0029, accordingly). An improvement in the outcome was found in the analyzed period of time, with a trend of better survival in patients treated under the AML-BFM 2012 and AML-BFM 2019 protocols compared to the AML-BFM 2004 protocol (5-year EFS 0.52 vs. 0.27, p = 0.069). There was a trend of improved outcomes in patients treated with FLT3 inhibitors (n = 9, 2-year EFS 0.67 vs. 0.33, p = 0.053) and those who received stem cell transplantation (SCT) (n = 26; 5-year EFS 0.70 vs. 0.27, p = 0.059). The co-occurrence of the WT1 mutation had a dismal impact on the prognosis (5-year EFS 0.23 vs. 0.69, p = 0.002), while the NPM1 mutation improved survival (5-year OS 1.0 vs. 0.44, p = 0.036). CONCLUSIONS: It seems that SCT and FLT3 inhibitors have a beneficial impact on the prognosis. Additional genetic alterations, like the WT1 and NPM1 mutations, significantly influence the outcome.

Incidence of bacterial and fungal infections in Polish pediatric patients with acute lymphoblastic leukemia during the pandemic.

The most common complications related to the treatment of childhood acute lymphoblastic leukemia (ALL) are infections. The aim of the study was to analyze the incidence and mortality rates among pediatric patients with ALL who were treated in 17 Polish pediatric hematology centers in 2020-2021 during the pandemic. Additionally, we compared these results with those of our previous study, which we conducted in the years 2012-2017. The retrospective analysis included 460 patients aged 1-18 years with newly diagnosed ALL. In our study, 361/460 (78.5%) children were reported to have microbiologically documented bacterial infections during chemotherapy. Ten patients (2.8%) died due to sepsis. Fungal infections were reported in 99 children (21.5%), of whom five (5.1%) died due to the infection. We especially observed an increase in bacterial infections during the pandemic period compared to the previous study. The directions of our actions should be to consider antibiotic prophylaxis, shorten the duration of hospitalization, and educate parents and medical staff about complications (mainly infections) during anticancer therapy. It is necessary to continue clinical studies evaluating infection prophylaxis to improve outcomes in childhood ALL patients.

MicroRNA gene methylation landscape in pediatric B-cell precursor acute lymphoblastic leukemia.

BACKGROUND: Aberrant DNA methylation is an important mechanism by which the normal patterns of microRNA expression are disrupted in human cancers including B-cell precursor acute lymphoblastic leukemia (BCP ALL), the most common pediatric malignancy. OBJECTIVES: To characterize the methylation profile landscape of microRNA genes in BCP ALL patients. MATERIAL AND METHODS: We employed Infinium® MethylationEPIC BeadChip Arrays to measure the methylation of microRNA genes from bone marrow samples of children with BCP ALL (n = 38) and controls without neoplasms (n = 4). RESULTS: This analysis revealed differential methylation of the microRNA genes in the pediatric BCP ALL when compared to the control. A subcluster amongst BCP ALL patients with TCF3-PBX1 genetic subtype was also observed. No other differences were observed in association with age, gender or risk group. Several interesting leukemia-related phenotypes are enriched by the genes with hyperand hypomethylated sites located in promoters as well as gene bodies. The top 3 miRNA genes, promoters of which were the most statistically significantly hypermethylated in BCP ALL were MIR1273G, MIR1304 and MIR663, and the top 3 hypomethylated were MIR4442, MIR155 and MIR3909. CONCLUSIONS: In this study, a different microRNA genes methylation landscape was shown in pediatric BCP ALL compared to children without neoplasms. A visible subcluster among BCP ALL samples consisted of individuals with TCF3-PBX1 genetic subtype. No other differences were observed in association with age, gender or risk group. Several interesting leukemia-connected phenotypes were found, associated with genes with hyperand hypomethylated sites located on promoters as well as gene bodies.