Impact of newborn screening for SCID on the management of congenital athymia.

BACKGROUND: Newborn screening (NBS) programs for severe combined immunodeficiency facilitate early diagnosis of severe combined immunodeficiency and promote early treatment with hematopoietic stem cell transplantation, resulting in improved clinical outcomes. Infants with congenital athymia are also identified through NBS because of severe T-cell lymphopenia. With the expanding introduction of NBS programs, referrals of athymic patients for treatment with thymus transplantation have recently increased at Great Ormond Street Hospital (GOSH) (London, United Kingdom). OBJECTIVE: We studied the impact of NBS on timely diagnosis and treatment of athymic infants with thymus transplantation at GOSH. METHODS: We compared age at referral and complications between athymic infants diagnosed after clinical presentation (n = 25) and infants identified through NBS (n = 19) who were referred for thymus transplantation at GOSH between October 2019 and February 2023. We assessed whether age at time of treatment influences thymic output at 6 and 12 months after transplantation. RESULTS: The infants referred after identification through NBS were significantly younger and had fewer complications, in particular fewer infections. All deaths occurred in the group of those who did not undergo NBS, including 6 patients before and 2 after thymus transplantation because of preexisting infections. In the absence of significant comorbidities or diagnostic uncertainties, timely treatment was achieved more frequently after NBS. Treatment when younger than age 4 months was associated with higher thymic output at 6 and 12 months after transplantation. CONCLUSION: NBS contributes to earlier recognition of congenital athymia, promoting referral of athymic patients for thymus transplantation before they acquire infections or other complications and facilitating treatment at a younger age, thus playing an important role in improving their outcomes.

Efficacy and Safety of Eculizumab in Pediatric Patients Affected by Shiga Toxin-Related Hemolytic and Uremic Syndrome: A Randomized, Placebo-Controlled Trial.

SIGNIFICANCE STATEMENT: Shiga toxin-related hemolytic uremic syndrome (STEC-HUS) is a serious condition, characterized by multiorgan thrombotic microangiopathy, mainly affecting children. Renal involvement is severe, with approximately half of patients requiring dialysis. So far, no specific treatment has been proven efficient in STEC-HUS. The use of eculizumab, a monoclonal antibody inhibiting terminal complement complex, has demonstrated remarkable success in atypical hemolytic uremic syndrome, but its use in uncontrolled studies to treat STEC-HUS has yielded inconsistent results. In this Phase 3 randomized, placebo-controlled trial in 100 pediatric patients with STEC-HUS, the findings did not show efficacy of eculizumab during the acute phase of the disease. However, the results indicated a reduction of renal sequelae in eculizumab-treated patients at 1-year follow-up. Larger prospective studies would be needed to further explore eculizumab as a potential treatment. BACKGROUND: Shiga toxin-related hemolytic uremic syndrome (STEC-HUS) in children is a severe condition, resulting in approximately 50% of patients requiring RRT. Furthermore, at least 30% of survivors experience kidney sequelae. Recently, activation of the complement alternative pathway has been postulated as a factor in STEC-HUS pathophysiology, leading to compassionate use of eculizumab, a monoclonal antibody inhibiting the terminal complement complex, in affected patients. Given the lack of therapy for STEC-HUS, a controlled study of eculizumab efficacy in treating this condition is a priority. METHODS: We conducted a Phase 3 randomized trial of eculizumab in children with STEC-HUS. Patients were randomly assigned in a 1:1 ratio to receive either eculizumab or placebo during 4 weeks. Follow-up lasted for 1 year. The primary end point was RRT duration <48 hours after randomization. Secondary endpoints included hematologic and extrarenal involvement. RESULTS: Baseline characteristics were similar among the 100 patients who underwent randomization. The rate of RRT <48 hours did not differ significantly between the two groups (48% in the placebo versus 38% in the eculizumab group; P = 0.31) or in the course of ARF. The two groups also exhibited similar hematologic evolution and extrarenal manifestations of STEC-HUS. The proportion of patients experiencing renal sequelae at 1 year was lower in the eculizumab group than in the placebo group (43.48% and 64.44%, respectively, P = 0.04). No safety concern was reported. CONCLUSIONS: In pediatric patients with STEC-HUS, eculizumab treatment does not appear to be associated with improved renal outcome during acute phase of the disease but may reduce long-term kidney sequelae. CLINICAL TRIALS REGISTRATIONS: EUDRACT (2014-001169-28) ClinicalTrials.gov ( NCT02205541 ).

Late toxicity comparison of alkylating-based maintenance regimen with cyclophosphamide (VAC) vs ifosfamide (VAI) in Ewing sarcoma survivors treated in the randomized clinical trial Euro-EWING99-R1 in France.

In Euro-EWING99-R1 randomized trial, cyclophosphamide was shown to be noninferior to ifosfamide in the consolidation of standard-risk Ewing sarcoma (SR-EWS) after a common induction with VIDE (vincristine-ifosfamide-doxorubicin-etoposide). We present the results of the late effects analysis of VAC (vincristine-dactinomycin-cyclophoshamide) vs VAI (vincristine-dactinomycin-ifosfamide) conducted in Euro-EWING99-R1 French cohort. Of 267 French randomized patients, 204 were alive and free-of-relapse at 5-years including 172 with available long-term follow-up data concerning cardiac, renal and/or gonadal functions (sex-ratio M/F = 1.3, median age at diagnosis = 14 years): 84 randomized in VAC (median cumulative doses: cyclophosphamide = 9.7 g/m2 , ifosfamide = 59.4 g/m2 ) and 88 in VAI (ifosfamide = 97.1 g/m2 ). With a median follow-up of 10 years (range = 5-17), five late relapses and five second malignancies were recorded. The 10-year event-free survival among 5-year free-of-relapse survivors was similar between VAC and VAI (93% vs 95%, P = .63). We estimated the 10-year cumulative probabilities of cardiac and kidney toxicities at 4.4% (95% confidence interval [95% CI] = 1.1%-7.6%) and 34.8% (95% CI = 26.8%-42.0%), respectively. Cardiac toxicity cumulative probability was similar in both arms, whereas kidney toxicity was higher in VAI (at 10 years, 43.0% vs 25.7%, P = .02), resulting from significant difference in glomerular toxicity (31.1% vs 13.1%, P < .01). At 10 years, gonadal toxicity was observed in 27% and 28% of pubertal men and women, respectively, without significant difference between VAC and VAI. Kidney and gonadal toxicities represent major issues in Euro-EWING99-R1, with significantly higher risk of kidney toxicities with VAI, without significant gonadal toxicity reduction. These results support the need to limit cumulative doses of both alkylating agents and to use mixed regimen as in VIDE-VAC or VDC/IE (vincristine-doxorubicin-cyclophoshamide/ifosfamide-etoposide).

Childhood ovarian nonseminomatous germ cell tumors: A highly curable disease with few long-term treatment-related toxicities-Results of the French TGM95 study.

We report survival and late effects analysis of TGM95 study for childhood (≤18 years) ovarian nonseminomatous germ cell tumors (NS-GCT). Patients with localized tumors (FIGO-stage IA) had no adjuvant treatment (low-risk, LR). Patients with advanced-stage received 3-5 VBP (vinblastin-bleomycin-cisplatin) in intermediate-risk group (IR: FIGO-stage IC-II-III and AFP < 15 000 ng/mL) or 4-6 VIP (etoposide-ifosfamide-cisplatin) in high-risk group (HiR: metastatic or AFP ≥ 15 000 ng/mL). Seventy-seven patients were included (median age = 12 years): 14 LR (13 FIGO-stage IA, 1 retrospectively IC), 26 IR (12 IC, 12 II-III, 2 not-available) and 37 HiR (2 IA with AFP ≥ 15 000 ng/mL, 27 II-III, 8 IV). After a median follow-up of 13.4 years, 12 events (eight relapses) and six deaths (two GCT-related, two due to acute myeloid leukemia and two noncancer related) occurred. All relapses (6 LR, 1 IR) occurred within 2 years. Four contralateral mature teratomas were observed within 8 years. Five-year EFS and OS were 88.2% (95%CI = 79-94%) and 94.6% (95%CI = 87-98%). Seven patients (9%) had bilateral gonadectomy. Among 51 survivors at 2 years aged >15 years (median = 26 years) with remaining ovarian tissue, all had developed spontaneous puberty and 21 (41%) had at least one pregnancy (including two with infertility treatment). Among 69 patients treated with platinum-based chemotherapy, chronic-kidney-disease was diagnosed in four patients (three after VIP) and significant ototoxicity occurred in three (all grade-2). Childhood ovarian NS-GCTs have an excellent prognosis with few late effects. The low-intensive etoposide-free VBP regimen could be an alternative in children with IR disease especially in cases of tumor rupture. The risk of contralateral mature teratoma needs regular monitoring of the remaining ovary.

Tumor rupture in hepatoblastoma: A high risk factor?

BACKGROUND: Hepatoblastoma tumor rupture is a high-risk criterion in the SIOPEL 3/4 protocol. Little is known about the outcome of these children. METHODS: Radiological signs of possible tumor rupture, defined as peritoneal effusion, peritoneal nodules, or hepatic subcapsular hematoma, were reported in 24 of 150 patients treated for hepatoblastoma in France from January 2000 to December 2014 after central radiological expert review. RESULTS: Twenty-two patients with available clinical data were included (nine PRETEXT-I/II, six PRETEXT-III, seven PRETEXT-IV, and five had lung metastases). Five patients had a subcapsular hematoma only, and 17 patients had intraperitoneal rupture (subcapsular hematoma and peritoneal effusion). A hepatic biopsy was performed in 19 patients. Intraperitoneal rupture occurred before biopsy in 12 and after biopsy in three (including one with prebiopsy subcapsular hematoma) (missing data: two). All patients were treated with chemotherapy, with high-risk regimens including cisplatin or carboplatin and doxorubicin in 19 and cisplatin or carboplatin alone in three. Liver surgery was performed in 20 patients (including three liver transplants). Fifteen patients (68%) achieved complete remission. With a median follow-up of 5.5 years, 11 events occurred (six progressions and three relapses, including three peritoneal progressions/relapses, one surgical complication, and one second cancer) and eight patients died. One of eight patients with no other high-risk criterion had a relapse. The three-year event-free survival and overall survival rates were 49.6% (95% CI = 30-69) and 68.2% (40-84), respectively. CONCLUSIONS: Tumor rupture is predictive of poor prognosis with risk of peritoneal progression/relapse. However, it should not be a contraindication for liver transplantation.

New insights into diagnosis and therapeutic options for proliferative hepatoblastoma.

Surgery and cisplatin-based treatment of hepatoblastoma (HB) currently guarantee the survival of 70%-80% of patients. However, some important challenges remain in diagnosing high-risk tumors and identifying relevant targetable pathways offering new therapeutic avenues. Previously, two molecular subclasses of HB tumors have been described, C1 and C2, with C2 being the subgroup with the poorest prognosis, a more advanced tumor stage, and the worst overall survival rate. An associated 16-gene signature to discriminate the two tumoral subgroups was proposed, but it has not been transferred into clinical routine. To address these issues, we performed RNA sequencing of 25 tumors and matched normal liver samples from patients. The transcript profiling separated HB into three distinct subgroups named C1, C2A, and C2B, identifiable by a concise four-gene signature: hydroxysteroid 17-beta dehydrogenase 6, integrin alpha 6, topoisomerase 2-alpha, and vimentin, with topoisomerase 2-alpha being characteristic for the proliferative C2A tumors. Differential expression of these genes was confirmed by quantitative RT-PCR on an expanded cohort and by immunohistochemistry. We also revealed significant overexpression of genes involved in the Fanconi anemia (FA) pathway in the C2A subgroup. We then investigated the ability of several described FA inhibitors to block growth of HB cells in vitro and in vivo. We demonstrated that bortezomib, a Food and Drug Administration-approved proteasome inhibitor, strongly impairs the proliferation and survival of HB cell lines in vitro, blocks FA pathway-associated double-strand DNA repair, and significantly impedes HB growth in vivo. CONCLUSION: The highly proliferating C2A subtype is characterized by topoisomerase 2-alpha gene up-regulation and FA pathway activation, and the HB therapeutic arsenal could include bortezomib for the treatment of patients with the most aggressive tumors. (Hepatology 2018;68:89-102).

Treatment and outcome of congenital nephrotic syndrome.

BACKGROUND: Recommendations for management of Finnish-type congenital nephrotic syndrome (CNS) followed by many teams include daily albumin infusions, early bilateral nephrectomy, dialysis and transplantation. We aimed to assess the treatment and outcome of patients with CNS in France. METHODS: We conducted a nationwide retrospective study on 55 consecutive children born between 2000 and 2014 treated for non-infectious CNS. RESULTS: The estimated cumulative incidence of CNS was 0.5/100 000 live births. The underlying defect was biallelic mutations in NPHS1 (36/55, 65%), NPHS2 (5/55, 7%), PLCE1 (1/55, 2%), heterozygous mutation in WT1 (4/55, 7%) and not identified in nine children (16%). Fifty-three patients (96%) received daily albumin infusions from diagnosis (median age 14 days), which were spaced and withdrawn in 10 patients. Twenty children (35%) were managed as outpatients. Thirty-nine patients reached end-stage kidney disease (ESKD) at a median age of 11 months. The overall renal survival was 64% and 45% at 1 and 2 years of age, respectively. Thirteen children died during the study period including four at diagnosis, two of nosocomial catheter-related septic shock, six on dialysis and one after transplantation. The remaining 13 patients were alive with normal renal function at last follow-up [median 32 months (range 9-52)]. Renal and patient survivals were longer in patients with NPHS1 mutations than in other patients. The invasive infection rate was 2.41/patient/year. CONCLUSIONS: Our study shows: (i) a survival free from ESKD in two-thirds of patients at 1 year and in one-half at 2 years and (ii) a significant reduction or even a discontinuation of albumin infusions allowing ambulatory care in a subset of patients. These results highlight the need for new therapeutic guidelines for CNS patients.

Renal failure in pediatric Castleman disease: Four French cases with thrombotic microangiopathy.

Pediatric Castleman disease (CD) is an uncommon and poorly understood disorder of the lymph nodes. Renal failure has not been described in pediatric multicentric CD (MCD). We report four cases, who presented with polyadenopathy, organomegaly, edema and fluid accumulations, high blood pressure, and acute renal failure. In all cases, renal biopsy confirmed diffuse thrombotic microangiopathy. Definitive diagnosis of MCD was made by a biopsy of an affected lymph node located by computer tomography before initiation of corticosteroid therapy. Treatment of CD with corticosteroid therapy and rituximab was rapidly effective without relapse to date.

Feasibility and clinical integration of molecular profiling for target identification in pediatric solid tumors.

BACKGROUND: The role of tumor molecular profiling in directing targeted therapy utilization remains to be defined for pediatric tumors. We aimed to evaluate the feasibility of a sequencing and molecular biology tumor board (MBB) program, and its clinical impact on children with solid tumors. PROCEDURE: We report on a single-center MBB experience of 60 pediatric patients with a poor prognosis or relapsed/refractory solid tumors screened between October 2014 and November 2015. Tumor molecular profiling was performed with panel-based next-generation sequencing and array comparative genomic hybridization. RESULTS: Mean age was 12 ± 5.7 years (range 0.1-21.5); main tumor types were high-grade gliomas (n = 14), rare sarcomas (n = 9), and neuroblastomas (n = 8). The indication was a poor prognosis tumor at diagnosis for 16 patients and relapsed (n = 26) or refractory disease (n = 18) for the remaining 44 patients. Molecular profiling was feasible in 58 patients. Twenty-three patients (40%) had a potentially actionable finding. Patients with high-grade gliomas had the highest number of targetable alterations (57%). Six of the 23 patients subsequently received a matched targeted therapy for a period ranging from 16 days to 11 months. The main reasons for not receiving targeted therapy were poor general condition (n = 5), pursuit of conventional therapy (n = 6), or lack of pediatric trial (n = 4). CONCLUSIONS: Pediatric molecular profiling is feasible, with more than a third of patients being eligible to receive targeted therapy, yet only a small proportion were treated with these therapies. Analysis at diagnosis may be useful for children with very poor prognosis tumsors.

Keep in Mind Quality of Life: Outcome of a Ten-Year Series of Post-Transplantation Early Relapses in Childhood Acute Lymphoblastic Leukemia-A Report from the Grand Ouest Oncology Study Group for Children in France.

Relapses of acute lymphoblastic leukemia (ALL) early after hematopoietic stem cell transplantations in children are uncommon but associated with a very poor prognosis. Whereas there are no current recommendations for the management of these relapses, the children's quality of life is an important issue. We studied the outcomes, including 1-year overall survival, complete remission, and quality of life, of 19 children with ALL who relapsed within the first year after their transplantation treated in the 5 participating centers between 2000 and 2011 Patients were distributed as follows: supportive care only (group A), outpatient treatment (mainly steroid and vincristine, group B), or intensive inpatient treatment (group C). There were no significant differences in 1-year overall survival (31.5% for the entire cohort) or remission rate for time between transplantation and relapse (< 6 months or 6 to 12 months), transplantation or disease characteristics, or treatment group. However, time spent in hospital (for treatment and complications) significantly differed between treatment groups B and C (20.8% ± 13.0 versus 59.1% ± 32.9, respectively; P < .05). No differences in organ toxicities, school attendance, or Lansky scores were found between treatment groups. Our sample size-limited data indicate, in a prepersonalized medicine era, that children treated with steroid and vincristine have the same prognosis as those treated with intensive therapy, but they may benefit from improved quality of life. Nevertheless, new therapeutic strategies are required and future prospective trials would help to establish recommendations.

Synovial sarcoma relapses in children and adolescents: prognostic factors, treatment, and outcome.

INTRODUCTION: Twenty-five to 32% of patients with synovial sarcoma (SS) relapse after appropriate treatment, and experience a poor outcome. Patients who can be salvaged by second-line therapy need to be more clearly identified. PATIENTS AND METHODS: Data of patients treated in SFCE (Société Française des Cancers de l'Enfant) centers with an initial diagnosis of localized SS before the age of 18 years and treated from 1/1988 to 12/2008, and who experienced at least one relapse, were retrieved. After descriptive analysis, statistical analysis was performed to determine prognostic factors. RESULTS: Thirty-seven patients were identified. First relapse occurred after a median interval of 24 months and was localized in 73.0% of cases and metastatic in 24.3% of cases. Treatment of relapse consisted of new surgery in 75.7% of cases, second-line chemotherapy in 73.0% of cases and radiotherapy in 48.6% of cases. Response rate to ifosfamide-based regimens was 36.4%. Overall, 70.3% patients achieved a second complete remission. Median 5-year-event-free survival was 32.8% and 5-year overall survival was 42.1%. Factors significantly correlated with better survival were primary tumor involving the limbs, age less than 12 years at diagnosis, absence of chemotherapy or radiotherapy as initial treatment and local relapse. CONCLUSION: Despite its poor overall outcome, relapse of synovial sarcoma sometimes remains curable. Aggressive surgery, when possible, in combination with chemotherapy and radiotherapy is the recommended treatment. Ifosfamide-based regimens may remain effective in patients with relapsed SS. However, alternative therapies should be proposed in patients with poor prognostic factors.

Hearing loss during osteosarcoma chemotherapy: when acute ifosfamide toxicity revealed unnoticed methotrexate encephalopathy.

Ifosfamide and methotrexate are widely used for the treatment of pediatric osteosarcoma. However, both these chemotherapeutic drugs can cause encephalopathy. A 17-year-old girl presented with profound hearing loss and dizziness during a postoperative course of ifosfamide, 20 days after a course of methotrexate. Cerebral magnetic resonance imaging (MRI) showed bilateral white matter hypersignal in Fluid Attenuated Inversion Recovery sequences. The clinical evolution was rapidly favorable after methylene blue infusion. This is the second reported case of acute deafness, possibly associated with ifosfamide, whereas MRI data revealed unnoticed chronic methotrexate toxicity. Systematic MRI screening and hearing evaluation may be useful in such cases.

TCF2/HNF-1beta mutations: 3 cases of fetal severe pancreatic agenesis or hypoplasia and multicystic renal dysplasia.

OBJECTIVE: The aim of this study was to document the association between pancreatic agenesis or hypoplasia and multicystic renal dysplasia related to transcription factor 2 (TCF2) or hepatocyte nuclear factor 1 beta mutations. METHODOLOGY: We describe the phenotype of the pancreas and the kidneys from three fetuses heterozygous for a mutation of TCF2. CASES: Case 1 had bilateral hyperechogenic, multicystic kidneys, bilateral clubfoot and pancreatic agenesis. Case 2 had two enlarged polycystic kidneys, anamnios and pancreatic agenesis. Case 3 had multicystic renal dysplasia, oligohydramnios and hypoplasia of the tail of the pancreas. CONCLUSION: TCF2 mutations are frequently discovered in fetuses presenting with bilateral hyperechogenic kidneys. The association between pancreatic agenesis and a TCF2 mutation has not previously been reported. TCF2 deficiency in mice leads to pancreatic agenesis, suggesting that the gene is essential for pancreatic development. Our observations indicate the importance of visualizing the pancreas during ultrasound examinations if renal malformations are discovered.

Standardization of the management of rheumatoid purpura nephropathy in the West of France. What are the repercussions on the renal sequelae?

Introduction: Rheumatoid purpura is the most common vasculitis in children, and its renal involvement determines the prognosis. To date, no national protocol exists for its management. A protocol was drafted for the French Grand Ouest inter-region in 2011 in order to standardize practices. Objectives: The main objective is to evaluate renal sequelae with a median follow-up of 2 years since the implementation of this protocol. The secondary objectives are to evaluate the different therapeutic and diagnostic management. Method: Inclusion of all children from 2006 to 2018 with nephropathy due to rheumatoid purpura followed in the university hospitals of Rennes, Nantes, Tours, Angers and Brest. Results: 169 patients were included, of whom 104 were treated accroding to protocol and 65 differently. Sequels at 2-year follow-up concerned 27.0% of patients with no significant difference according to whether or not the protocol was followed. A significant decrease of 26.1% in the number of renal biopsies was observed in the group that followed the protocol. The latter was performed with a median delay of less than 30 days. Conclusion: The protocol allowed a standardization of practices without deleterious consequences at 2 years of follow-up and a decrease in renal biopsy punctures. It is in agreement with the recommendations of KDIGO (Kidney Disease Improving Global Outcomes) and European experts. On the other hand, in view of recent studies and the physiopathology, immunosuppressive drugs other than corticosteroids could be introduced earlier in severe forms.

Introduction: Le purpura rhumatoïde est la vascularite la plus fréquente chez l'enfant, dont l'atteinte rénale détermine le pronostic. Aucun protocole national n'existe à ce jour concernant sa prise en charge. Un protocole a été rédigé sur le Grand Ouest de la France en 2011 afin d'uniformiser les pratiques. Objectifs: L'objectif principal est d'évaluer les séquelles rénales avec une médiane de suivi de deux ans depuis la mise en place de ce protocole. Les objectifs secondaires sont d'évaluer les différentes prises en charge thérapeutiques et diagnostiques. Méthodes: Nous avons inclus tous les enfants de 2006 à 2018 ayant présenté une néphropathie due à un purpura rhumatoïde suivis dans les CHU de Rennes, Nantes, Tours, Angers et Brest. Résultats: Au total, 169 patients ont été inclus, dont 104 respectant le protocole et 65 hors protocole. Les séquelles à deux ans de suivi concernent 27 % des patients sans différence significative selon l'application ou non du protocole. Une diminution significative de 26,1 % des ponctions biopsies rénales est observée dans le groupe respectant le protocole. Cette dernière est réalisée avec un délai médian inférieur à 30 jours. Conclusion: Le protocole réalisé par le Grand Ouest a permis une uniformisation des pratiques sans conséquences délétères à deux ans de suivi et une diminution des ponctions biopsies rénales. Il est en accord avec les recommandations du KDIGO (Kidney Disease Improving Global Outcomes) et des experts européens. En revanche, au vu des études récentes et de la physiopathologie, les immunosuppresseurs hors corticothérapies pourraient être intégrés plus précocement dans les formes sévères.

Single-cell multiomics reveals the interplay of clonal evolution and cellular plasticity in hepatoblastoma.

Hepatoblastomas (HB) display heterogeneous cellular phenotypes that influence the clinical outcome, but the underlying mechanisms are poorly understood. Here, we use a single-cell multiomic strategy to unravel the molecular determinants of this plasticity. We identify a continuum of HB cell states between hepatocytic (scH), liver progenitor (scLP) and mesenchymal (scM) differentiation poles, with an intermediate scH/LP population bordering scLP and scH areas in spatial transcriptomics. Chromatin accessibility landscapes reveal the gene regulatory networks of each differentiation pole, and the sequence of transcription factor activations underlying cell state transitions. Single-cell mapping of somatic alterations reveals the clonal architecture of each tumor, showing that each genetic subclone displays its own range of cellular plasticity across differentiation states. The most scLP subclones, overexpressing stem cell and DNA repair genes, proliferate faster after neo-adjuvant chemotherapy. These results highlight how the interplay of clonal evolution and epigenetic plasticity shapes the potential of HB subclones to respond to chemotherapy.

Mutational signature, cancer driver genes mutations and transcriptomic subgroups predict hepatoblastoma survival.

BACKGROUND: Hepatoblastoma is the most frequent pediatric liver cancer. The current treatments lead to 80% of survival rate at 5 years. In this study, we evaluated the clinical relevance of molecular features to identify patients at risk of chemoresistance, relapse and death of disease. METHODS: All the clinical data of 86 children with hepatoblastoma were retrospectively collected. Pathological slides were reviewed, tumor DNA sequencing (by whole exome, whole genome or target) and transcriptomic profiling with RNAseq or 300-genes panel were performed. Associations between the clinical, pathological, mutational and transcriptomic data were investigated. RESULTS: High-risk patients represented 44% of our series and the median age at diagnosis was 21.9 months (range: 0-208). Alterations of the WNT/ß-catenin pathway and of the 11p15.5 imprinted locus were identified in 98% and 74% of the tumors, respectively. Other cancer driver genes mutations were only found in less than 11% of tumors. After neoadjuvant chemotherapy, disease-specific survival and poor response to neoadjuvant chemotherapy were associated with 'Liver Progenitor' (p = 0.00049, p < 0.0001) and 'Immune Cold' (p = 0.0011, p < 0.0001) transcriptomic tumor subtypes, SBS35 cisplatin mutational signature (p = 0.018, p = 0.001), mutations in rare cancer driver genes (p = 0.0039, p = 0.0017) and embryonal predominant histological type (p = 0.0013, p = 0.0077), respectively. Integration of the clinical and molecular features revealed a cluster of molecular markers associated with resistance to chemotherapy and survival, enlightening transcriptomic 'Immune Cold' and Liver Progenitor' as a predictor of survival independent of the clinical features. CONCLUSIONS: Response to neoadjuvant chemotherapy and survival in children treated for hepatoblastoma are associated with genomic and pathological features independently of the clinical features.

Seasonality of main childhood embryonal tumours and rhabdomyosarcoma, France, 2000-2015.

Few studies have investigated the seasonal patterns of embryonal tumours. Based on data from the French National Registry of Childhood Cancers, the present study aimed to investigate seasonal variations in embryonal tumour incidence rates by month of birth and by month of diagnosis. The study included 6635 primary embryonal tumour cases diagnosed before the age of 15 years over the period 2000-2015 in mainland France. Assuming monthly variations in incidence rates were homogeneous over 2000-2015, we used a Poisson regression model to test for overall heterogeneity in standardised incidence ratios (SIRs) by month of birth or diagnosis. The seasonal scan statistic method was used to detect monthly excesses or deficits of embryonal tumour cases over the whole study period. The annual reproducibility of the observed monthly variations was formally tested. An overall heterogeneity in incidence rates by month of birth was observed for rhabdomyosarcoma in boys only. Based on the month of diagnosis, a seasonality was evidenced for unilateral retinoblastoma, with a lower incidence rate in the summer (SIRJul-Aug  = 0.68, 95% CI = 0.52-0.87), whilst the incidence rate of rhabdomyosarcoma tended to be lower in August (SIRAug  = 0.68, 95% CI = 0.52-0.89). No seasonality was detected for the other embryonal tumour groups by month of birth or month of diagnosis. This study is one of the largest to have investigated the seasonality of childhood embryonal tumours. The study showed a seasonal variation in the incidence rates by month of diagnosis for unilateral retinoblastoma and rhabdomyosarcoma. Our findings are likely to reflect a delay in consultation during the summer months. However, the role of seasonally varying environmental exposures cannot be ruled out.

Preneoplastic liver colonization by 11p15.5 altered mosaic cells in young children with hepatoblastoma.

Pediatric liver tumors are very rare tumors with the most common diagnosis being hepatoblastoma. While hepatoblastomas are predominantly sporadic, around 15% of cases develop as part of predisposition syndromes such as Beckwith-Wiedemann (11p15.5 locus altered). Here, we identify mosaic genetic alterations of 11p15.5 locus in the liver of hepatoblastoma patients without a clinical diagnosis of Beckwith-Wiedemann syndrome. We do not retrieve these alterations in children with other types of pediatric liver tumors. We show that mosaic 11p15.5 alterations in liver FFPE sections of hepatoblastoma patients display IGF2 overexpression and H19 downregulation together with an alteration of the liver zonation. Moreover, mosaic livers' microenvironment is enriched in extracellular matrix and angiogenesis. Spatial transcriptomics and single-nucleus RNAseq analyses identify a 60-gene signature in 11p15.5 altered hepatocytes. These data provide insights for 11p15.5 mosaicism detection and its functional consequences during the early steps of carcinogenesis.

Severe hematopoietic stem cell inflammation compromises chronic granulomatous disease gene therapy.

X-linked chronic granulomatous disease (CGD) is associated with defective phagocytosis, life-threatening infections, and inflammatory complications. We performed a clinical trial of lentivirus-based gene therapy in four patients (NCT02757911). Two patients show stable engraftment and clinical benefits, whereas the other two have progressively lost gene-corrected cells. Single-cell transcriptomic analysis reveals a significantly lower frequency of hematopoietic stem cells (HSCs) in CGD patients, especially in the two patients with defective engraftment. These two present a profound change in HSC status, a high interferon score, and elevated myeloid progenitor frequency. We use elastic-net logistic regression to identify a set of 51 interferon genes and transcription factors that predict the failure of HSC engraftment. In one patient, an aberrant HSC state with elevated CEBPß expression drives HSC exhaustion, as demonstrated by low repopulation in a xenotransplantation model. Targeted treatments to protect HSCs, coupled to targeted gene expression screening, might improve clinical outcomes in CGD.