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Abstract 2615 Background: Infants (age Patients & Methods: JPLSG AML-05 study, registered at http://www.umin.ac.jp/ctr/as UMIN000000511, is a nation-wide multi-institutional study and recruited 447 eligible children (age Results: The median follow-up period for living patients was 3.06 years (range, 0.84 – 5.36 years). Although, there was no difference in 3-year probability of event-free survival (pEFS) between infants and patients ≥1 year old [56.0% (95%CI, 38.7 – 70.1%) vs. 55.2% (49.8 – 60.2%) (p = 0.63)], 3-year probability of overall survival (pOS) in infants was inferior; 56.0% (95%CI, 37.9 – 70.7%) vs. 75.0% (70.0 – 79.4%) (p = 0.011). When the outcome of infants were compared with patients 1 - The inferiority of pOS in infants compared to the patients 1 - Conclusions: Our experience suggests that appropriate chemotherapeutic dose modification in induction therapy to avoid early deaths is essential in treating infants with de novo AML. As dose intensification approach is difficult to apply for this age subgroup, incorporation of less toxic targeted agents based on biological features is needed to attain better outcome for infants with AML. Disclosures: No relevant conflicts of interest to declare.

Abstract 4799 Background: Rapid identification and quantification of abnormal cell populations in minimal specimen are crucial for diagnosis and longitudinal minimal residual disease (MRD) testing of childhood leukemia. So far, most standard immunophenotypic analyses are performed using antibody panels with up to five-colors and require high cell numbers. For infant and pediatric specimen, high-level multicolor analyses is highly desirable to gather sufficient data for initial diagnostic and follow up monitoring of pathologic populations. Objective: In this study, we aimed to establish a newly defined pediatric multicolor flow cytometric panel algorithm with high reliability yet minimal specimen requirement. Results: We defined a 10-color flow cytometric panel using the new violet laser dye “KromeOrange (KO)”. Applying CD45-KO/Side Scatter gating, combined with 2 additional backbone markers the panel is designed in two consecutive steps. In the first step, a single standardized 10-color-“screening tube” (FITC-HLA-DR, PE-CD15/CD56, ECD-CD5, PC5.5-CD33, PC7-CD13, APC-CD117, APC A700-CD34, APC A750-CD19, PB-CD3, KrO-CD45) is applied for initial orientation of specific lineage assignment. Based on results obtained with the screening tube, a specific multi-tube “classification panel” is used to complete detailed characterization of lineage specific malignancy and maturation stage. Suitable specimens include fresh blood, bone marrow and all body fluids. All samples are stained directly with monoclonal antibodies, followed by the lyses of erythrocytes and a short wash. Compared to standard five color panel previously used the application of greater numbers of informative antibodies in the screening tube and in the 2ndstep muti-tube classification panel is cost and time efficient and results in a more precise characterization of any single event. Conclusion: Our panel construction and algorithm definition for infant and pediatric leukemia immunophenotyping is one of the first 10-color flow cytometry panels described for this application. Advantages are the possibility to obtain highly specific information from minimal specimens with significantly improved laboratory efficiency. The overall performance is currently tested in a routine clinical setting. Disclosures: No relevant conflicts of interest to declare.

Clinical observations suggest that poor nutrition worsens outcomes for pediatric leukemia patients undergoing therapy. However, the molecular basis for this observation is not well understood. Ample data indicates that increased cellular oxidative stress is an important mechanism of action of chemotherapeutic regimens used for pediatric acute leukemias. Reports also suggest that diet may modulate the balance of cellular pro- and antioxidants. Here, we propose that age appropriate adequate nutrition promotes endogenous metabolic sources of oxidative stress, which when combined with chemotherapy induced oxidative stress, provide better outcomes for these patients. Assessments of nutrition and oxidative stress were completed for each patient at regularly scheduled intervals over a six month period. Changes in nutrition and oxidative stress were monitored. Nutrition was quantified by conducting 24 hour dietary recalls. Data was entered into the Minnesota Nutrition Data System for Research (NDSR) dietary analysis program. Cellular oxidative stress in mononuclear cells isolated from peripheral blood was also quantified. Specifically, intracellular superoxide and hydrogen peroxide were measured with dihydroethidium (HE) and 2′,7α-dichlorofluorescin diacetate (DCF-DA) staining by flow cytometry, respectively. Glutathione (GSH), an antioxidant, was also measured by monochlorobimane staining. To date, analyses have been completed for 12 patients. An increase in superoxides was detected in 72.7% of patients (8 of 11). An increase in hydrogen peroxide was detected in 50% of patients (6 of 12). An increase was defined as a two-fold or greater elevation in ROS at any subsequent visit compared to the baseline visit. A decrease in GSH was seen in 50% of patients (6 of 12) and 33% (4 of 12) demonstrated a decrease in GSH coincident with an increase in both superoxides and hydrogen peroxide. This increase in ROS and decrease in GSH suggests that the majority of our patients experience oxidative stress during therapy. To investigate the impact of diet on oxidant status, NDSR software was used to compare the consumption of dietary antioxidants, such as vitamins A, B3, C, and E, selenium, and glutamic acid, to the corresponding amounts of ROS from the same visit. The strongest correlation was between vitamin C consumption and hydrogen peroxide levels. An inverse relationship between vitamin C consumption and hydrogen peroxide levels was apparent in 58.3% of patients (7 of 12). These data provide insight into the relationship between diet and oxidative stress in pediatric leukemia patients. Future work will support the design of dietary interventions that will modulate oxidant status to favor improved survival of children with leukemia. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5434. doi:1538-7445.AM2012-5434

Chromosomal translocations of the mixed lineage leukemia (MLL) gene occur in 5-10% of pediatric acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), including up to 80% of infant ALL and most treatment-related secondary AML. These MLL rearrangements result in a portion of the MLL protein being fused to one of a number of transcription factors. The prognosis for MLL-rearranged (MLL-R) leukemia is much poorer than for leukemia devoid of MLL fusions; five-year survival of Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1375. doi:10.1158/1538-7445.AM2011-1375

Optimizing the therapeutic strategies based on the results of randomized studies comparing different regimens led to a better prognosis of nearly all pediatric malignancies during the past four decades. Fever and neutropenia (FN) is a common complication in patients undergoing chemotherapy to treat cancer. There is no consensus on when standard therapy can be safely reduced; this lack of consensus leads to important variations in management of FN between different institutions, usually conducted according to local attitudes. To address this issue, the Infection working group of the Italian association for pediatric hematology oncology (AIEOP) organized a consensus meeting. This paper reports the agreement derived from this meeting.

Abstract 1025 Introduction: Infantile acute lymphoblastic leukemia (ALL) is a rare leukemia subtype in infants with poor prognosis. Its outcome has gradually improved due to the development of treatment, including intensive chemotherapy or hematopoietic stem cell transplantation (SCT). However, prognosis of relapsed patients is extremely poor, which prompt us to establish the new treatment strategy for them. To establish the future treatment strategy for the relapsed cases, we here investigated the incidence of relapse, treatment, prognosis, and possible risk factors of relapsed cases with infantile ALL treated by the Japanese Pediatric Leukemia /Lymphoma Study Group (JPLSG) MLL03 study. Subjects: All relapsed cases with infantile ALL who underwent the MLL03 study between April 2004 and June 2009 were eligible for the study. The questionnaires were sent to all participants, asking the relapsed patients with infantile ALL by the MLL03 study. The questionnaires consisted of the time and site of relapse, treatment after relapse, presence or absence of remission prior to the second SCT, conditioning regimen for the second SCT, and age, white blood cell count, and presence or absence of central nervous system (CNS) infiltration at initial onset. Results: Total 63 patients were treated in this study period (mean follow-up, 31.8 months). Among them, 24 patients relapsed at any site after first complete remission (38%). These include 7 boys and 17 girls. Age at onset was less than 6 months in 19, and 6–12 months in 5. The overall survival (OS) rate of 24 patients was 60.2 ± 11.1% at 3 years; 44.6 ± 12.7% at 4 years, and 23.5 ± 13.4% at 5 years. Twenty-one of 24 patients (87.5%) relapsed after initial SCT; only three patients (12.5%) relapsed before SCT. Two patients relapsed early within 6 months after initial treatment terminally died. All four patients who relapsed at extramedullary site except CNS have survived, suggesting better prognosis. Patients diagnosed at age of less than 6 months also showed poor prognosis after relapse (5 year OS rate was 14.9 ± 13.0%). Presence or absence of remission prior to the second SCT was not a significant prognostic factor (28.3 ± 21.8% versus 15.6 ± 14.2%). Discussion: In the JPLSG MLL03 study, 38% of patients with infantile ALL relapsed. Only four patients relapsed prior to the initial SCT, indicating that the aim of the MLL03 study, to reduce the early relapse rate by performing the early SCT, could have been achieved. On the other hand, 87.5% of the patients relapsed after initial SCT in this study. Most of them were less than 6 months at onset. Several reasons for the high relapse rate after SCT should be considered, which include low graft-versus-leukemia (GVL) effect for infantile ALL, remained minimal residual disease (MRD) before SCT, or inappropriate conditioning regimen in this study. Since we have analyzed MRD before and after SCT in each patient treated by the MLL03 study, one reason could be resolved. In addition, the treatment strategy to induce GVL effect for infantile ALL should be established and we should reconsider the treatment strategy. Finally, appropriate treatment strategy for relapsed cases should be organized in the future. Disclosures: No relevant conflicts of interest to declare.

PURPOSE: Although age at diagnosis is a surrogate prognostic factor, it remains an important predictor of pediatric leukemia survival. However, it is not fully understood which prognostic factors are directly related to its effect on survival. We aimed in this study to assess the effect of age at diagnosis on childhood leukemia survival. METHODS: We utilized data from Surveillance Epidemiology and End Result (SEER) of newly diagnosed leukemia (nZ15,215) from 1973–2006. Data on sex, race, clinical subtypes of leukemia, children aged 0–19 years involving 17 SEER registries were assessed for overall and age at diagnosis related survival. The Kaplan-Meier, log rank test, and Cox proportional hazard methods were used to examine the impact of age on survival. RESULTS:Theoverall 5 year survival ratewas 67.9%.There was a statistically significant difference in survival by age group at diagnosis, sex, race, tumor cell type, p! 0.0001. This variability persisted after adjustment for the relevant covariates. Compared to infants, children 1–4 years were 76% less likely to die from leukemia (Adjusted Hazard Ratio (AHR) Z 0.24, 99% CIZ0.21–0.28, Children 5–9 years (AHRZ0.31, 99% CI Z 0.26–0.36), children 10–14 years (AHRZ 0.54, 99% CIZ0.46–0.62) and children 15–19 years (AHRZ0.82, 99% CIZ0.70–0.95) CONCLUSIONS:Age at diagnosis remains a single potent predictor of survival in pediatric leukemia, and infants as well as children 15–19 years present with the worst survival. Since age at diagnosis per se does not influence survival but is related to biological and/or clinical tumor prognostic factors, this study adjusted for the effect of some of these factors but survival variability by age at diagnosis persisted. Therefore, identification of such factors will ensure a meaningful explanation of the impact of age at tumor diagnosis on survival.

e20005 Background: Leukemia is the most common malignancy in the pediatric age group. To understand the molecular basis of leukemogenesis we examined gene expression patterns. One of the genes expr...

10043 Background: To observe the therapeutic efficacy of unrelated donor umbilical cord blood transplantation(UCBT) and unrelated donor bone marrow transplantation(UBMT) in pediatric Leukemia. Meth...

9528 Background: The alkylating agent temozolomide exerts its primary cytotoxic activity through the addition to O6 methyl adducts to guanine residues in DNA, and temozolomide resistance results either from increased expression of methyl-guanine DNA methyltransferase (MGMT), which removes O6 adducts, or from mutations in the mismatch repair system (MRS), which lead to microsatellite instability (MSI). Temozolomide also creates N3 and N7 methyl adducts that are efficiently removed by the base excision repair (BER) system. PARP inhibitors block BER and may potentiate the cytotoxic effects of temozolomide. Methods: The cytotoxicity of temozolomide in combination with the PARP inhibitor ABT-888 was evaluated in vitro in leukemia cell lines and primary leukemia cells using the MTT assay. PARP activity was measured using a commercially available PARP assay. Results: ABT-888 effectively enhanced temozolomide cytotoxicity in cell lines with elevated MGMT (Jurkat and HSB2 T-cell ALL cell lines) or MRS deficiencies (Jurkat and Molt-4 T cell ALL). The temozolomide IC50 decreased from 450 μM to 35 μM at an ABT-888 concentration of 5 μM in the Jurkat T-cell ALL cell line and from 340 μM to 7.5 μM in the HSB2 T-cell line. ABT-888 also enhanced temozolomide cytotoxicity in non-T-cell leukemia subtypes, decreasing the IC50 in the JM1 pre-B ALL cell line from 51 μM to 7.7 μM and decreasing the IC50 from 316 μM to 22 μM in tumor cells obtained from a patient with pre-B ALL. PARP activity was also examined. In contrast, the sensitivity of U937 AML cells to temozolomide showed no effect of the addition of a PARP inhibitor. These results are consistent with the findings that these cells have low or undetectable MGMT and no MSI to suggest MRS mutations. Conclusion: These results suggest that ABT-888 may enhance the cytotoxic activity of temozolomide in leukemia patients whose tumors are resistant to temozolomide because of elevated MGMT expression and mismatch repair defects. No significant financial relationships to disclose.

8504 Background: Despite marked improvement in pediatric leukemia outcome, children with refractory disease or early relapse have a dismal prognosis with the current salvage regimens. Leukemia remains the leading cause of disease-related death in children. New therapeutic options are needed. Clofarabine, a next-generation nucleoside analogue, has shown clinical activity when used as a single agent in heavily pretreated children with relapsed or refractory acute leukemias. Methods: Two Phase 2 multicenter, open-label studies are being conducted with clofarabine in children with refractory or relapsed ALL or AML. Clofarabine is administered at 52 mg/m2/day over 5 consecutive days. Cycles are repeated every 2 to 6 weeks based on response and toxicity. Results: To date 69 patients (40 ALL, 29 AML) have been treated. Median age is 12 years (range 1 to 22 years) and median prior regimens is 3 (range 1 to 6). Forty-one percent had received prior transplant. As determined by independent review, preliminary data i...

Purpose: To evaluate the MR imaging findings and the usefulness of MR imaging in the diagnosis and follow-up of leukoencephalopathy following CNS prophylaxis therapy in pediatric leukemia. Materials and Methods: We retrospectively evaluated the MR imaging findings of eight children with white matter abnormalities on MR out of seventeen acute leukemic patients with various neuropsychiatric symptoms who received intrathecal methotrexate administration, with or without cranial irradiation. In all cases, initial MR was performed within a week of the onset of neuropsychiatric symptoms. Follow-up MR was performed one to sixteen months after initial study, and the MR imaging findings were compared with the initial findings. Results: The initial MR imaging findings were classified into three categories: focal or multifocal white matter abnormalities (3/8), and diffuse white matter abnormalities without enhancement (3/8), and diffuse white matter abnormalities with enhancement (2/8). At follow-up MR, diffuse or focal atrophic changes were noted in all children. White matter abnormalities improved in two out of three patients with focal or multifocal white matter abnormalities. In five with diffuse white matter abnormalities, the extent of these showed no significant change, but contrast enhancement was markedly reduced in two children in whom diffuse white matter abnormalities with enhancement had been demonstrated. Conclusion: In pediatric leukemia, the MR imaging findings of leukoencephalopathy following CNS prophylaxis therapy are variable, but are specific with the clinical history of neuropsychiatric symptoms after intrathecal methotrexate administration, with or without cranial irradiation. The MR imaging is valuable in the diagnosis and follow-up of leukoencephalopathy following CNS prophylaxis therapy in pediatric leukemia.

As part of a longitudinal research study, families of children with leukemia were provided with a psychosocial intervention program over a two-year period. This paper describes the approaches used at specific times during the illness: diagnosis and initial treatment, early outpatient treatment, later outpatient treatment, remission, relapse, and death. the goals of the intervention strategies were to facilitate: an understanding of the realities of the illness; management of emotional distress; and utilization of resources to care for the child, attend to other responsibilities, and support and communicate with one another.

Newly diagnosed children with leukemia and their families were subjects of a longitudinal study to describe coping behaviors, to determine adequacy of coping, and to discover predictors of healthy coping with leukemia. Families were followed for six months during which time they were interviewed, completed tests and scales, and were rated by physicians, nurses, and psychosocial staff. Families showed a wide variety of reactions and coping behaviors. The data supported the hypothesis that most families cope well despite the stresses of the first six months post-diagnosis. Based on physicians' ratings, psychosocial intervention appeared to be effective for mothers during the early outpatient phase of treatment. Age of child, previous coping, coping of other family members, a good support system, and lack of additional stresses were significantly correlated with healthy coping. The need for longitudinal assessment of coping was stressed.

// Chiara Palmi 1 , Angela M. Savino 1 , Daniela Silvestri 2, 3 , Ilaria Bronzini 4 , Gunnar Cario 5 , Maddalena Paganin 4 , Barbara Buldini 4 , Marta Galbiati 1 , Martina U. Muckenthaler 6 , Cristina Bugarin 1 , Pamela Della Mina 7 , Stefan Nagel 8 , Elena Barisone 9 , Fiorina Casale 10 , Franco Locatelli 11 , Luca Lo Nigro 12 , Concetta Micalizzi 13 , Rosanna Parasole 14 , Andrea Pession 15 , Maria C. Putti 4 , Nicola Santoro 16 , Anna M. Testi 17 , Ottavio Ziino 18 , Andreas E. Kulozik 6 , Martin Zimmermann 19 , Martin Schrappe 5 , Antonello Villa 7 , Giuseppe Gaipa 1 , Giuseppe Basso 4 , Andrea Biondi 3 , Maria G. Valsecchi 2 , Martin Stanulla 19 , Valentino Conter 3 , Geertruy te Kronnie 4 , Giovanni Cazzaniga 1 1 Centro Ricerca M. Tettamanti, Clinica Pediatrica, Universita di Milano Bicocca, Fondazione MBBM/Ospedale San Gerardo, Monza, Italy 2 Center of Biostatistics for Clinical Epidemiology, Department of Health Sciences, University of Milano-Bicocca, Milan, Italy 3 Clinica Pediatrica, Universita di Milano Bicocca, Fondazione MBBM/Ospedale San Gerardo, Monza, Italy 4 Laboratory of Onco-Hematology, Department SDB, Universita di Padova, Padova, Italy 5 Department of Pediatrics, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany 6 Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg and EMBL/Medical Faculty Molecular Medicine Partnership Unit, Heidelberg, Germany 7 Microscopy and Image Analysis Consortium, Universita di Milano-Bicocca, Monza, Italy 8 Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany 9 Pediatric Onco-Hematology, Stem Cell Transplantation and Cellular Therapy Division, Regina Margherita Children’s Hospital, Turin, Italy 10 Pediatric Oncology Service, Pediatric Department of 2nd University of Naples, Naples, Italy 11 Department of Pediatric Hematology/Oncology, IRCCS Ospedale Bambino Gesu, Rome - University of Pavia, Pavia, Italy 12 Center of Pediatric Hematology Oncology, Azienda Ospedaliero-Universitaria “Policlinico Vittorio Emanuele”, Catania, Italy 13 Hematology/Oncology Unit, G. Gaslini Children’s Hospital, Genoa, Italy 14 Department of Pediatric Hemato-Oncology, Ospedale Pausilipon, Napoli, Italy 15 Department of Pediatrics, “Lalla Seragnoli” Hematology-Oncology Unit, University of Bologna, Bologna, Italy 16 Department of Pediatrics, Division of Pediatric Hematology-Oncology, University “A. Moro” of Bari, Bari, Italy 17 Division of Hematology, Department of Biotechnologies and Hematology, “Sapienza” University of Rome, Rome, Italy 18 Pediatric Hematology and Oncology Unit, A.R.N.A.S. Civico, Di Cristina and Benfratelli Hospital, Palermo, Italy 19 Department of Paediatric Haematology and Oncology, Hannover Medical School, Hannover, Germany Correspondence to: Giovanni Cazzaniga, email: gianni.cazzaniga@hsgerardo.org Andrea Biondi, email: abiondi.unimib@gmail.com Keywords: CRLF2, pediatric leukemia, T acute lymphoblastic leukemia, prognostic marker, high risk Received: May 20, 2016 Accepted: July 01, 2016 Published: July 15, 2016 ABSTRACT Pediatric T-ALL patients have a worse outcome compared to BCP-ALL patients and they could benefit from new prognostic marker identification. Alteration of CRLF2 gene, a hallmark correlated with poor outcome in BCP-ALL, has not been reported in T-ALL. We analyzed CRLF2 expression in 212 T-ALL pediatric patients enrolled in AIEOP-BFM ALL2000 study in Italian and German centers. Seventeen out of 120 (14.2%) Italian patients presented CRLF2 mRNA expression 5 times higher than the median ( CRLF2-high ); they had a significantly inferior event-free survival (41.2%±11.9 vs. 68.9%±4.6, p=0.006) and overall survival (47.1%±12.1 vs. 73.8%±4.3, p=0.009) and an increased cumulative incidence of relapse/resistance (52.9%±12.1 vs. 26.2%±4.3, p=0.007) compared to CRLF2-low patients. The prognostic value of CRLF2 over-expression was validated in the German cohort. Of note, CRLF2 over-expression was associated with poor prognosis in the high risk (HR) subgroup where CRLF2-high patients were more frequently allocated. Interestingly, although in T-ALL CRLF2 protein was localized mainly in the cytoplasm, in CRLF2-high blasts we found a trend towards a stronger TSLP-induced pSTAT5 response, sensitive to the JAK inhibitor Ruxolitinib. In conclusion, CRLF2 over-expression is a poor prognostic marker identifying a subset of HR T-ALL patients that could benefit from alternative therapy, potentially targeting the CRLF2 pathway.

Background An estimated 15,000 children and adolescents under the age of 19 years are diagnosed with leukemia, lymphoma and other tumors in the USA every year. All children and adolescent acute leukemia patients will undergo chemotherapy as part of their treatment regimen. Fortunately, survival rates for most pediatric cancers have improved at a remarkable pace over the past three decades, and the overall survival rate is greater than 90 % today. However, significant differences in survival rate have been found in different age groups (94 % in 1–9.99 years, 82 % in ≥10 years and 76 % in ≥15 years). ALL accounts for about three out of four cases of childhood leukemia. Intensive chemotherapy treatment coupled with prophylactic or therapeutic antibiotic use could potentially have a long-term effect on the resident gastrointestinal (GI) microbiome. The composition of GI microbiome and its changes upon chemotherapy in pediatric and adolescent leukemia patients is poorly understood. In this study, using 16S rRNA marker gene sequences we profile the GI microbial communities of pediatric and adolescent acute leukemia patients before and after chemotherapy treatment and compare with the microbiota of their healthy siblings. Results Our study cohort consisted of 51 participants, made up of matched pediatric and adolescent patients with ALL and a healthy sibling. We elucidated and compared the GI microbiota profiles of patients and their healthy sibling controls via analysis of 16S rRNA gene sequencing data. We assessed the GI microbiota composition in pediatric and adolescent patients with ALL during the course of chemotherapy by comparing stool samples taken before chemotherapy with stool samples collected at varying time points during the chemotherapeutic treatment. The microbiota profiles of both patients and control sibling groups are dominated by members of Bacteroides, Prevotella, and Faecalibacterium. At the genus level, both groups share many taxa in common, but the microbiota diversity of the patient group is significantly lower than that of the control group. It was possible to distinguish between the patient and control groups based on their microbiota profiles. The top taxa include Anaerostipes, Coprococcus, Roseburia, and Ruminococcus2 with relatively higher abundance in the control group. The observed microbiota changes are likely the result of several factors including a direct influence of therapeutic compounds on the gut flora and an indirect effect of chemotherapy on the immune system, which, in turn, affects the microbiota. Conclusions This study provides significant information on GI microbiota populations in immunocompromised children and opens up the potential for developing novel diagnostics based on stool tests and therapies to improve the dysbiotic condition of the microbiota at the time of diagnosis and in the earliest stages of chemotherapy. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2965-y) contains supplementary material, which is available to authorized users.

Background and aim Folate metabolic pathway plays a significant role in leukemogenesis because of its necessity for nucleotide synthesis and DNA methylation. Folate deficiency causes DNA damage. Thus polymorphisms of folate-related genes may affect the susceptibility to childhood Acute Lymphoblastic Leukemia (ALL). MTHFR (Methylenetetrahydrofolate Reductase), DHFR (Dihydrofolate reductase), CBS (Cystathionine ?-synthase) and TYMS (Thymidylate Synthase) have an important role in folate pathway because their activated variants modulate synthesis of DNA and levels of folate. In this study, we aimed to investigate whether polymorphisms in genes related to folate metabolic pathway influence the risk to childhood ALL. Subject and methods The patient groups who were diagnosed with childhood ALL at Losante Pediatric Hematology-Oncology Hospital and healthy control groups were included in the study. MTHFR 677 C-T, MTHFR 1298 A-C, CBS 844ins68, DHFR 19-bp and TYMS 1494del6 polymorphisms were screened. Genotyping of these polymorphisms was performed by Restriction Fragment Length Polymorphism (RFLP) analysis and Real Time Polymerase chain Reaction (Real Time-PCR). Results In total, we have screened 5 polymorphisms in the studied genes. The results were compared between childhood ALL patients and healthy groups. Genotype frequencies of MTHFR 677 C-T, MTHFR 1298 A-C, CBS 844ins68 and DHFR 19-bp del were similar for childhood ALL patients and healthy groups. However, statistical results showed that TYMS 1494del6 may be associated with ALL pathogenesis (p < 0.001). Conclusion We showed that TYMS polymorphism (rs2853542) may be associated with ALL pathogenesis. In addition, our results demonstrated that MTHFR, DHFR and CBS do not affect development of leukemia. Our study displays also importance as it is the first screening results to identify association with the studied polymorphisms in Turkish patients with childhood ALL and determination of the frequency in Turkish population. © 2017 Ain Shams University