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Pediatric cancer is rare. It is estimated that more than 10-15 % of tumors are secondary to a pathogenic variant in a cancer predisposition gene. More than 100 cancer predisposition genes and their association with syndromes or isolated tumors have been identified. Li-Fraumeni syndrome is one of those who have been most widely described. Patients with this syndrome present a high risk of developing one or more tumors. Its knowledge allows to establish a follow-up protocol for the patient and affected family members, so as to detect new tumors in an early manner and reduce tumorand treatment-related morbidity and mortality. The objective of this review is to offer useful guidelines for pediatricians. Based on a family case, reasons for Li-Fraumeni syndrome suspicion, clinical and genetic diagnosis, and the follow-up protocol of family members who carry the same mutation will be reviewed.El cáncer en pediatría es una entidad infrecuente. Se estima que más de un 10-15 % de los tumores son secundarios a una variante patogénica en un gen de predisposición al cáncer. Se conocen más de 100 genes de predisposición al cáncer y su asociación con síndromes o tumores aislados. Uno de los más descritos es el síndrome de Li-Fraumeni. Los pacientes con este síndrome tienen alto riesgo de desarrollar uno o más tumores. Su conocimiento permite realizar un protocolo de seguimiento del paciente y de sus familiares afectos, con el que detectar precozmente nuevos tumores y disminuir la morbimortalidad del tumor y de su tratamiento. Esta revisión pretende ser una guía útil para el pediatra. Utilizando como caso guía a una familia, se revisarán los motivos de sospecha de un síndrome de Li-Fraumeni, su diagnóstico clínico y genético, y el protocolo de seguimiento de los familiares portadores de la misma mutación.

People with Down syndrome have unique characteristics as a result of the presence of an extra chromosome 21. Regarding cancer, they present a unique pattern of tumors, which has not been fully explained to date. Globally, people with Down syndrome have a similar lifetime risk of developing cancer compared to the general population. However, they have a very increased risk of developing certain tumors (e.g., acute leukemia, germ cell tumors, testicular tumors and retinoblastoma) and, on the contrary, there are some other tumors which appear only exceptionally in this syndrome (e.g., breast cancer, prostate cancer, medulloblastoma, neuroblastoma and Wilms tumor). Various hypotheses have been developed to explain this situation. The genetic imbalance secondary to the presence of an extra chromosome 21 has molecular consequences at several levels, not only in chromosome 21 but also throughout the genome. In this review, we discuss the different proposed mechanisms that protect individuals with trisomy 21 from developing solid tumors: genetic dosage effect, tumor suppressor genes overexpression, disturbed metabolism, impaired neurogenesis and angiogenesis, increased apoptosis, immune system dysregulation, epigenetic aberrations and the effect of different microRNAs, among others. More research into the molecular pathways involved in this unique pattern of malignancies is still needed. post-print 1107 KB

Background & Aims: Hepatoblastoma (HB) is a rare disease. Nevertheless, it is the predominant pediatric liver cancer, with limited therapeutic options for patients with aggressive tumors. Herein, we aimed to uncover the mechanisms of HB pathobiology and to identify new biomarkers and therapeutic targets in a move towards precision medicine for patients with advanced HB. Methods: We performed a comprehensive genomic, transcriptomic and epigenomic characterization of 159 clinically annotated samples from 113 patients with HB, using high-throughput technologies. Results: We discovered a widespread epigenetic footprint of HB that includes hyperediting of the tumor suppressor BLCAP concomitant with a genome-wide dysregulation of RNA editing and the overexpression of mainly non-coding genes of the oncogenic 14q32 DLK1-DIO3 locus. By unsupervised analysis, we identified 2 epigenomic clusters (Epi-CA, Epi-CB) with distinct degrees of DNA hypomethylation and CpG island hypermethylation that are associated with the C1/C2/C2B transcriptomic subtypes. Based on these findings, we defined the first molecular risk stratification of HB (MRS-HB), which encompasses 3 main prognostic categories and improves the current clinical risk stratification approach. The MRS-3 category (28%), defined by strong 14q32 locus expression and Epi-CB methylation features, was characterized by CTNNB1 and NFE2L2 mutations, a progenitor-like phenotype and clinical aggressiveness. Finally, we identified choline kinase alpha as a promising therapeutic target for intermediate and high-risk HBs, as its inhibition in HB cell lines and patient-derived xenografts strongly abrogated tumor growth. Conclusions: These findings provide a detailed insight into the molecular features of HB and could be used to improve current clinical stratification approaches and to develop treatments for patients with HB. Lay summary: Hepatoblastoma is a rare childhood liver cancer that has been understudied. We have used cutting-edge technologies to expand our molecular knowledge of this cancer. Our biological findings can be used to improve clinical management and pave the way for the development of novel therapies for this cancer. (c) 2020 European Association for the Study of the Liver. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)., This article was possible thanks to the inputs from the Instituto de Salud Carlos III, ISCIII (PI09/00751, PI10/02082, PI13/02340). The project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 668596 (ChiLTERN) and grant agreement No 826121 (iPC). JCR is supported by the Catalan Agency for Management of University and Research Grants (AGAUR, 2019 FI_B01024). LT is supported by an Accelerator Award (CRUCK, AECC, AIRC) (HUNTER, C9380/A26813). DS is supported by the Gilead Research Scholar in Liver Disease. JML is supported by the European Union's Horizon 2020 research and innovation programme (HEPCAR, 667273-2), Institucio Catalana de Recerca i Estudis Avancats (ICREA), U.S. Department of Defense (CA150272P3), an Accelerator Award (CRUCK, AECC, AIRC) (HUNTER, C9380/A26813), National Cancer Institute, Tisch Cancer Institute (P30-CA196521), Samuel Waxman Cancer Research Foundation, Spanish National Health Institute (SAF2016-76390) and AGAUR (SGR-1358). CA and MRS were supported by Ramon y Cajal (RYC-2010-07249) and Miguel Servet (CPII14/00021) programs of the Ministry of Science and Innovation of Spain and ISCIII, respectively. CA, MRS and MS received funding from CIBERehd (CB06/04/0033) and AGAUR (2017-SGR-490). IGTP is a member of the CERCA network of institutes. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Hemophagocytic lymphohistiocytosis (HLH) is a condition caused by a pathologic immune activation, which is responsible for its signs and symptoms. It may also appear as a secondary process caused by malignancy. Developing HLH during treatment for acute lymphoblastic leukemia (ALL) is extremely uncommon, but underdiagnosis may be fatal. Two patients with ALL on chemotherapy maintenance treatment who developed HLH triggered by infection are presented here. We emphasize the importance of being aware of this condition when a patient with ALL in complete remission presents with unexplained hepatomegaly, cytopenia, and fever. Early diagnosis and treatment may be lifesaving.

Pediatric Central Nervous System (CNS) tumors are the most fatal cancer diseases in childhood. Due to their localization and infiltrative nature, some tumor resections or biopsies are not feasible. In those cases, the use of minimally invasive methods as diagnostic, molecular marker detection, prognostic or monitoring therapies are emerging. The analysis of liquid biopsies which contain genetic information from the tumor has been much more widely explored in adults than in children. We compare the detection of BRAF V600E targetable mutation by digital-PCR from cell-free-DNA and EV-derived DNA (ctDNA) in serum, plasma and cerebrospinal fluid (CSF) isolated from a cohort of 29 CNS pediatric patients. Here we demonstrate that ctDNA isolated from serum and plasma could be successfully analyzed to obtain tumor genetic information which could be used to guide critical treatment decisions.

Philadelphia-chromosome acute lymphoblastic leukaemia (Ph+ ALL) is a subgroup of ALL with very high risk of treatment failure. We report here the results of the Sociedad Espanola de Hematologia y Oncologia Pediatricas (SEHOP/SHOP) in paediatric Ph+ ALL treated with intermediate-dose imatinib concurrent with intensive chemotherapy. The toxicities and outcome of these patients were compared with historical controls not receiving imatinib. Patients with Ph+ ALL aged 1-18 years were enrolled in three consecutive ALL/SHOP trials (SHOP-94/SHOP-99/SHOP-2005). In the SHOP-2005 trial, imatinib (260 mg/m(2) per day) was given on day-15 of induction. Allogeneic haematopoietic stem-cell transplantation (HSCT) from a matched related or unrelated donor was scheduled in first complete remission (CR1). Forty-three patients were evaluable (22 boys, median age 6.8 years, range, 1.2-15). Sixteen received imatinib whereas 27 received similar chemotherapy without imatinib. Seventeen of 27 and 15 of 16 patients in the non-imatinib and imatinib cohort, respectively, underwent HSCT in CRI. With a median follow-up of 109 and 39 months for the non-imatinib and imatinib cohorts, the 3-year event-free survival (EFS) was 29.6% and 78.7%, respectively (P = 0.01). These results show that, compared to historical controls, intermediate dose of imatinib given concomitantly with chemotherapy and followed by allogeneic HSCT markedly improved early EFS in paediatric Ph+ ALL.

Infants and very young children with malignant brain tumors usually have unfavourable locations and are not candidates for craniospinal irradiation. New therapeutic approaches must be attempted to improve poor survival rates. The primary goal of the present study was to report on the safety profile and toxicity of intrathecal administration of liposomal cytarabine in children

We analyzed the outcome in 22 children with refractory or relapsed non-Hodgkin lymphoma who underwent autologous peripheral blood progenitor cell transplantation between 1994 and 2009. The conditioning regimen used in all patients consisted of busulfan and cyclophosphamide. Median age was 6 years (range 2 to 16 y). The most common histologic subtype was Burkitt lymphoma. Ten patients were in complete remission and 12 in partial remission at the time of transplant. The median dose of CD34+ cells that was infused was 4.6 × 10/kg (range 2.1 to 58.7 × 10/kg). All the patients were engrafted, with a median time for neutrophils and platelets recovery of 11 (range, 8 to 15 d) and 14 (range, 9 to 60 d) days, respectively. Nonhematologic treatment-related toxicity included severe mucositis in 3 patients and hepatic sinusoidal obstruction syndrome in 1 patient. There were no transplant-related mortalities. With a median follow-up of 60 months (range, 4 to 180 d) the disease-free survival was 90 ± 6.5% for the whole group. This retrospective study shows a high long-term survival using busulfan/cyclophosphamide as conditioning regimen in children with refractory or relapsed non-Hodgkin lymphoma.

To assess the efficacy and safety of liposomal cytarabine in the treatment of de novo and relapsed leptomeningeal involvement in children with primary CNS tumours. Data from clinical charts were entered into a database for consecutive unselected patients (n=20) from nine Spanish centres. Diagnosis of leptomeningeal involvement was confirmed by cytology, MRI and/or CT scan. The dose of liposomal cytarabine used varied from 20 to 50 mg, by age. There were 8 females and 12 males, mean age 7.3 years (range 8 months to 18 years). The tumours were: 10 medulloblastomas, 4 ependymomas, 3 primitive neuroectodermal tumours and 3 other tumours. Fourteen had undergone previous chemotherapy and 12 radiotherapy. Nine received concurrent chemotherapy and 2 concurrent radiotherapy. Median follow-up was 244.5 days (range 12–869). Patients received a median of 5 doses (range 1–9) of liposomal cytarabine. A neurological response (complete or partial) was seen in 11/19 (58%) and a cytological response in 7/10 (64%). Median time to neurological progression exceeded 180 days (range 12–869). Adverse effects were reported in 11/20 patients, but none was grade IV. Liposomal cytarabine was well tolerated and efficacious in this patient group, but prospective randomised trials are needed.