Current status of precision medicine in pediatric oncology in Spain: a consensus report by the Spanish Society of Paediatric Haematology and Oncology (SEHOP).

The study analyzes the current status of personalized medicine in pediatric oncology in Spain. It gathers national data on the tumor molecular studies and genomic sequencing carried out at diagnosis and at relapse, the centers that perform these studies, the technology used and the interpretation and clinical applicability of the results. Current challenges and future directions to achieve a coordinated national personalized medicine strategy in pediatric oncology are also discussed. Next generation sequencing-based (NGS) gene panels are the technology used in the majority of centers and financial limitations are the main reason for not incorporating these studies into routine care. Nowadays, the application of precision medicine in pediatric oncology is a reality in a great number of Spanish centers. However, its implementation is uneven and lacks standardization of protocols; therefore, national coordination to overcome the inequalities is required. Collaborative work within the Personalized Medicine Group of SEHOP is an adequate framework for encouraging a step forward in the effort to move precision medicine into the national healthcare system.

Minimally invasive surgery for pediatric dumbbell neuroblastoma: systematic literature review and report of a single-stage neurosurgical and thoracoscopic approach.

INTRODUCTION: Traditional surgical strategies for dumbbell neuroblastoma entail, among others, high risk of spinal deformity. Less invasive procedures might reduce these sequelae, however, there is small evidence comparing different strategies. Indications of minimally invasive surgery in neuroblastoma are still developing. Our aim is to identify and analyze different surgical approaches described in the recent literature and to suggest a minimally invasive option. METHODS: A systematic review of the literature was conducted in PubMed (Jan 2000-Dec 2021) to identify reports describing surgical resection of dumbbell neuroblastoma in children, according to the PRISMA guidelines. Only full-text articles were included. RESULTS: 7 articles met the inclusion criteria which, added to the present case, represent a total of 43 patients. All were retrospective studies, most of them small series. Tumor location was mostly thoracic. Most of combined approaches were performed in two stages. Spinal deformity after surgery was reported in 3 patients. Minimally invasive approach was described in only one paper, with no reported cases of its use in a single-stage combined surgery. We also report, to our knowledge, the first single-stage posterior neurosurgical approach combined with thoracoscopy for resection of a dumbbell neuroblastoma in an infant. CONCLUSION: Surgical resection of dumbbell neuroblastomas is challenging. There is no consensus on best surgical approach. Dumbbell tumors should not be considered a contraindication for minimally invasive surgery. A single stage and minimally invasive strategy is proposed.

Multidisciplinary consensus on optimising the detection of NTRK gene alterations in tumours.

The recent identification of rearrangements of neurotrophic tyrosine receptor kinase (NTRK) genes and the development of specific fusion protein inhibitors, such as larotrectinib and entrectinib, have revolutionised the diagnostic and clinical management of patients presenting with tumours with these alterations. Tumours that harbour NTRK fusions are found in both adults and children; and they are either rare tumours with common NTRK fusions that may be diagnostic, or more prevalent tumours with rare NTRK fusions. To assess currently available evidence on this matter, three key Spanish medical societies (the Spanish Society of Medical Oncology (SEOM), the Spanish Society of Pathological Anatomy (SEAP), and the Spanish Society of Paediatric Haematology and Oncology (SEHOP) have brought together a group of experts to develop a consensus document that includes guidelines on the diagnostic, clinical, and therapeutic aspects of NTRK-fusion tumours. This document also discusses the challenges related to the routine detection of these genetic alterations in a mostly public Health Care System.

Challenges in early phase clinical trials for childhood cancer during the COVID-19 pandemic: a report from the new agents group of the Spanish Society of Paediatric Haematology and Oncology (SEHOP).

PURPOSE: The COVID-19 pandemic has forced healthcare stakeholders towards challenging decisions. We analyse the impact of the pandemic on the conduct of phase I-II trials for paediatric cancer during the first month of state of alarm in Spain. METHODS: A questionnaire was sent to all five ITCC-accredited Spanish Paediatric Oncology Early Phase Clinical Trial Units, including questions about impact on staff activities, recruitment, patient care, supply of investigational products, and legal aspects. RESULTS: All units suffered personnel shortages and difficulties in enrolling patients, treatment continuity, or performing trial assessments. Monitoring activity was frequently postponed (73%), and 49% of on-going trials interrupted recruitment. Only two patients could be recruited during this period (75% reduction in the expected rate). CONCLUSIONS: The COVID-19 crisis has significantly impacted clinical research practice and access to innovation for children with cancer. Structural and functional changes are under way to better cope with the expected future restrictions.

miRNA-7 and miRNA-324-5p regulate alpha9-Integrin expression and exert anti-oncogenic effects in rhabdomyosarcoma.

The prognosis of patients with metastatic rhabdomyosarcoma (RMS), the most common type of soft tissue sarcoma in children, is poor and no strategies have been identified to improve their dismal prognosis. Alpha-9 integrin (ITGA9) plays a particularly crucial role in cancer progression and invasiveness. Despite the consensus on the remarkable pro-oncogenic potential of this protein, the miRNA-mediated regulation of ITGA9 has barely been studied to date. In the present study, miR-7 and miR-324-5p were selected as the best candidates after a screening to find ITGA9 regulators, and their effects on cell proliferation and invasion in RMS are described and characterized for the first time. Interestingly, the overexpression of both miRNA produced a clear impairment of cell proliferation, while miR-7 also induced a remarkable drop in cell invasion. Furthermore, the stable overexpression of both miRNA was found to reduce tumor growth in orthotopic RMS models and miR-7 was able to impair metastatic lung colonization. Consequently, we conclude that miR-7 and miR-324-5p show anti-oncogenic and anti-metastatic potential, thereby opening up the possibility of being used as novel therapeutic tools to avoid RMS progression.

Patient-derived xenografts for childhood solid tumors: a valuable tool to test new drugs and personalize treatments.

The use of preclinical models is essential in translational cancer research and especially important in pediatric cancer given the low incidence of each particular type of cancer. Cell line cultures have led to significant advances in cancer biology. However, cell lines have adapted to growth in artificial culture conditions, thereby undergoing genetic and phenotypic changes which may hinder the translational application. Tumor grafts developed in mice from patient tumor tissues, generally known as patient-derived xenografts (PDXs), are interesting alternative approaches to reproducing the biology of the original tumor. This review is focused on highlighting the interest of PDX models in pediatric cancer research and supporting strategies of personalized medicine. This review provides: (1) a description of the background of PDX in cancer, (2) the particular case of PDX in pediatric cancer, (3) how PDX can improve personalized medicine strategies, (4) new methods to increase engraftment, and, finally, (5) concluding remarks.

[Survival analysis of hematopoietic stem cell transplantation in children with primary immunodeficiency in Spain]. / Análisis de la supervivencia de los niños con inmunodeficiencias primarias que han recibido un trasplante de progenitores hematopoyéticos en España.

INTRODUCTION: Children with primary immunodeficiency have severe life-threatening infections and a higher prevalence of autoimmune problems, allergy and lymphoproliferative disorders. Allogenic hematopoietic stem cell transplantation has been the only potentially curative option. PATIENTS AND METHODS: Patients with primary immunodeficiency underwent allogenic stem cell transplantation in the period 1985-2011, and registered in the Spanish Working Party for Bone Marrow Transplantation in Children. RESULTS: One hundred and fifty nine patients underwent 173 allogenic stem cell transplantations, of whom 97 had severe combined immunodeficiency, 30 with immune dysregulation disorders, 25 Wiskott-Aldrich syndrome, and 21 phagocyte disorders. The median patient age at diagnosis was 6 months (range: 17 days - 168 months) and the median patient age at transplant was 12 months (range: 1 month - 189 months). The donors were 30 (19%) identical siblings, 40 (25%) alternative family donors, and 89 (56%) unrelated donors. The source of stem cells was bone marrow in 68 (43%), cord blood in 52 (33%), and peripheral blood in 39 (24%). Ninety eight (61.6%) are alive, 57 (35.9%) died. Event-free survival at 10 years was 63%, with 90% for children transplanted from identical siblings, 36% for those transplanted from alternative family donors, and 66% for those transplanted from unrelated donors. CONCLUSIONS: The best results have been obtained with identical siblings, but other options may be considered.

[Results of hematopoietic stem cell transplantation in hemoglobinopathies: thalassemia major and sickle cell disease]. / Resultados del trasplante de progenitores hematopoyéticos en hemoglobinopatías: talasemia maior y enfermedad drepanocítica.

BACKGROUND: The prevalence of hemoglobinopathies in Spain is increasing as a result of immigration. Thalassemia major presents with chronic hemolytic anemia that requires regular red blood cell transfusions within the first year of life. Patients with sickle cell disease suffer from chronic anemia, vasculopathy and progressive damage in almost any organ. There is decreased life expectancy in both conditions. Allogeneic hematopoietic stem cell transplantation represents the only potentially curative option. PATIENTS: Seventeen patients (fourteen thalassemia major, and three sickle cell disease) underwent allogeneic hematopoietic stem cell transplantations. RESULTS: In the thalassemia group, nine donors were HLA-geno-identical siblings, two were partially matched related donors (one HLA allele mismatch), and three unrelated donors. All three patients with sickle cell disease were transplanted from HLA-geno-identical siblings. The source of stem cells was bone marrow in sixteen cases. Median patient age at transplant was six years (range: 1-16) in the thalassemia group, and twelve years (range: 8-15) in the sickle cell disease group. The graft was successful in all patients. Secondary graft rejection was observed in two thalassemia patients rendering them dependent on blood transfusions. Complete chimerism was observed in thirteen patients and, although mixed chimerism occurred in two, with all of them showing normal hemoglobin levels after transplantation and not requiring further transfusion support. Patients affected by sickle cell disease did not present with new vaso-occlusive crises, and stabilization of pulmonary and neurological function was observed. Chronic graft-versus-host disease was detected in three patients affected by thalassemia, and hypogonadotrophic hypogonadism in five patients. CONCLUSIONS: We conclude that for thalassemia major and sickle cell disease, allogenic hematopoietic stem cell transplantation from HLA-geno-identical siblings offers a high probability of complication-free survival. Despite good results, morbidity and mortality associated with transplantation from unrelated donors is a risk that might be considered, in contrast to a non-curative medical treatment that offers a long term survival. For thalassemia major groups it could be an option, but not for sickle cell disease, which is still in the investigational phase.