Milind Ronghe

Constitutional 11p15 abnormalities, including heritable imprinting center mutations, cause nonsyndromic Wilms tumor

Constitutional abnormalities at the imprinted 11p15 growth regulatory region cause syndromes characterized by disordered growth, some of which include a risk of Wilms tumor. We explored their possible contribution to nonsyndromic Wilms tumor and identified constitutional 11p15 abnormalities in genomic lymphocyte DNA from 13 of 437 individuals (3%) with sporadic Wilms tumor without features of growth disorders, including 12% of bilateral cases (P = 0.001) and in one familial Wilms tumor pedigree. No abnormality was detected in 220 controls (P = 0.006). Abnormalities identified included H19 DMR epimutations, uniparental disomy 11p15 and H19 DMR imprinting center mutations (one microinsertion and one microdeletion), thus identifying microinsertion as a new class of imprinting center mutation. Our data identify constitutional 11p15 defects as one of the most common known causes of Wilms tumor, provide mechanistic insights into imprinting disruption and reveal clinically important epigenotype-phenotype associations. The impact on clinical management dictates that constitutional 11p15 analysis should be considered in all individuals with Wilms tumor.

Dose-dense cisplatin-based chemotherapy and surgery for children with high-risk hepatoblastoma (SIOPEL-4): a prospective, single-arm, feasibility study

Summary Background The objective of this study was to establish the efficacy and safety of a new treatment regimen consisting of dose-dense cisplatin-based chemotherapy and radical surgery in children with high-risk hepatoblastoma. Methods SIOPEL-4 was a prospective single-arm feasibility study. Patients aged 18 years or younger with newly diagnosed hepatoblastoma with either metastatic disease, tumour in all liver segments, abdominal extrahepatic disease, major vascular invasion, low α fetoprotein, or tumour rupture were eligible. Treatment consisted of preoperative chemotherapy (cycles A1–A3: cisplatin 80 mg/m2 per day intravenous in 24 h on day 1; cisplatin 70 mg/m2 per day intravenous in 24 h on days 8, 15, 29, 36, 43, 57, and 64; and doxorubicin 30 mg/m2 per day intravenous in 24 h on days 8, 9, 36, 37, 57, and 58) followed by surgical removal of all remaining tumour lesions if feasible (including liver transplantation and metastasectomy, if needed). Patients whose tumour remained unresectable received additional preoperative chemotherapy (cycle B: doxorubicin 25 mg/m2 per day in 24 h on days 1–3 and 22–24, and carboplatin area under the curve [AUC] 10·6 mg/mL per min per day intravenous in 1 h on days 1 and 22) before surgery was attempted. After surgery, postoperative chemotherapy was given (cycle C: doxorubicin 20 mg/m2 per day in 24 h on days 1, 2, 22, 23, 43, and 44, and carboplatin AUC 6·6 mg/mL per min per day in 1 h on days 1, 22, and 43) to patients who did not receive cycle B. The primary endpoint was the proportion of patients with complete remission at the end of treatment. Analysis was by intention to treat. This trial is registered at ClinicalTrials.gov, NCT00077389. Findings We report the final analysis of the trial. 62 eligible patients (39 with lung metastases) were included and analysed. 60 (98%, 95% CI 91–100) of 61 evaluable patients (one child underwent primary hepatectomy) had a partial response to preoperative chemotherapy. Complete resection of all tumour lesions was achieved in 46 patients (74%). At the end of therapy, 49 (79%, 95% CI 67–88) of 62 patients were in complete remission. With a median follow-up of 52 months, 3-year event-free survival was 76% (95% CI 65–87) and 3-year overall survival was 83% (73–93). 60 (97%) patients had grade 3–4 haematological toxicity (anaemia, neutropenia, or thrombocytopenia) and 44 (71%) had at least one episode of febrile neutropenia. Other main grade 3 or 4 toxicities were documented infections (17 patients, 27%), anorexia (22, 35%), and mucositis (seven, 11%). One child died of fungal infection in neutropenia. Moderate-to-severe ototoxicity was documented in 31 (50%) patients. 18 serious adverse events (including two deaths) reflecting the observed side-effects were reported in the trial (the most common was ototoxicity in five patients). Interpretation The SIOPEL-4 treatment regimen is feasible and efficacious for complete remission at the end of treatment for patients with high-risk hepatoblastoma. Funding Cancer Research UK and Cancer Research Switzerland/Oncosuisse.

A genome-wide association study identifies susceptibility loci for Wilms tumor

Wilms tumor is the most common renal malignancy of childhood. To identify common variants that confer susceptibility to Wilms tumor, we conducted a genome-wide association study in 757 individuals with Wilms tumor (cases) and 1,879 controls. We evaluated ten SNPs in regions significantly associated at P < 5 × 10−5 in two independent replication series from the UK (769 cases and 2,814 controls) and the United States (719 cases and 1,037 controls). We identified clear significant associations at 2p24 (rs3755132, P = 1.03 × 10−14; rs807624, P = 1.32 × 10−14) and 11q14 (rs790356, P = 4.25 × 10−15). Both regions contain genes that are plausibly related to Wilms tumorigenesis. We also identified candidate association signals at 5q14, 22q12 and Xp22.

Efficacy of irinotecan single drug treatment in children with refractory or recurrent hepatoblastoma – A phase II trial of the childhood liver tumour strategy group (SIOPEL) ☆

PURPOSE To assess the clinical activity of irinotecan as single drug in children with refractory or recurrent hepatoblastoma. PATIENTS AND METHODS Four cycles of irinotecan were administered (20mg/m(2)/day intravenous (i.v.) infusion on days 1-5 and 8-12, every 21days) unless tumour progression occurred or resectability was achieved earlier. Tumour response was assessed according to modified SIOPEL and Response Evaluation Criteria In Solid Tumours (RECIST) criteria. Main end-points were best overall response rate (RR), early progression rate (EPR) and progression free survival (PFS). RESULTS Twenty-four eligible patients (median age 58.0months; 19 boys) were enrolled in the study (11 relapses, 13 refractory diseases). Of the 23 evaluable patients six had an overall partial response, 11 stable disease and six progressive disease, of which four were early progression (RR: 26%, EPR: 17%). In eight patients the residual tumour could be completely resected; seven patients became tumour free. At last follow-up 12 patients were alive (six with no evidence of disease, six with disease). PFS at 1year was 24%. Patients with relapse had a higher RR than patients with refractory disease (46% versus 8%) and patients with isolated lung lesions showed a better response than patients with other tumour localisations (50% versus 13%). The main grade 3-4 toxicities, diarrhoea and neutropenia, occurred in half of the patients. CONCLUSION Irinotecan has a significant anti-tumour activity and acceptable toxicity in patients with relapsed hepatoblastoma and therefore should be considered for the treatment of these patients. Exploration of the role of irinotecan in the initial treatment of hepatoblastoma is warranted.

Anticoagulation Therapy in Children

Thromboembolic disease (TED) is increasingly recognized as a major cause of morbidity and mortality in tertiary pediatrics. Children younger than 1 year of age and teenage girls are at greatest risk of thromboembolism.Although anticoagulation therapy is the treatment of choice for TED, the treatment strategy is often difficult, especially in children. Treatment relies largely on anticoagulation with heparin and warfarin. Recommendations for antithrombotic therapy in children have been loosely extrapolated from recommendations for adults; however, it is likely that optimal treatment of children with TED differs from adults because of important ontogenic features of hemostasis that affect both the pathophysiology of the thrombotic processes and the response to antithrombotic agents.Until recently, the primary treatment for TED has been unfractionated heparin (UFH) in conjunction with warfarin. Warfarin, the most commonly used oral anticoagulant, acts through inhibition of the vitamin K-dependent transcarboxylation reactions that convert precursors of clotting factors into their active form. Appropriate use of UFH and warfarin requires close patient monitoring and dosage adjustments to ensure tolerability and efficacy. In recent years, low molecular weight heparins (LMWH) have become available as alternatives to UFH and warfarin, for both the prevention and treatment of TED. Potentially, LMWH have significant advantages. They have superior pharmacokinetics, which results in minimal laboratory monitoring, offering important benefits to children with poor venous access. Based on available data, LMWHs are at least as effective and well tolerated as UFH, and are more convenient. Although LMWHs are more expensive than UFH, the expense is likely to be offset by savings from a reduced hospital stay.

Diffuse Intrinsic Pontine Gliomas

Brain stem tumors account for 10–15% of all primary childhood CNS tumors. Most of the brain tumors arising in the brain stem are gliomas. With recent advances in neuro-imaging, particularly the advent of magnetic resonance imaging (MRI) and careful correlation of clinical presentation, location, and growth pattern, it has become evident that brain stem tumors are a heterogeneous group of neoplasms, divisible into distinct subgroups, such as diffuse intrinsic pontine tumors and focal, dorsal exophytic, cervicomedullary tumors. Diffuse intrinsic pontine gliomas (DIPG) constitute 80% of the pediatric brain stem tumors. These tumors are typically highgrade gliomas and have uniformly poor prognosis.

Chemotherapy and Novel Cancer Targeted Therapies

Overall survival from childhood malignancies has dramatically improved, with survival rates now reaching over 70 %. Although improvements in radiotherapy and surgery have reduced the late sequelae of curative therapy, chemotherapy still remains the mainstay of treatment for most childhood cancers. Nevertheless, some types of childhood cancer remain a difficult challenge, and for those who survive the burden of late effects can be considerable. The current paradigm for new cancer therapies is to increase our knowledge of the molecular basis of carcinogenesis, followed by the development of cancer-cell specific therapies. During the past 10 years, initiatives have been undertaken by paediatric oncologists to further promote the clinical evaluation of new anti cancer compounds in children within national academic paediatric groups. Through proper evaluation in collaborative clinical trials we will learn how best to use these new therapeutic approaches and improve the survival rates and reduce toxicity for children with cancer.

Chemotherapy and Novel Targeted Therapies

Children’s cancers are rare and account for 1% of all malignancies. Within Europe this represents some 12,000 new cases each year, with approximately 1,600 per year in the UK. In the UK, 1 in every 600 children under 15 years of age develop cancer. Although rare, childhood cancer is the second commonest cause of death in children between 1–14 years of age. These cancers are quite different from cancers affecting adults. Most adult tumors are carcinomas and are usually classified by their site of origin, whereas pediatric tumors occur in different parts of the body, look different under the microscope, and are classified by histological subtypes. Tumor types that are common to both adults and children, such as lymphomas and leukemia, differ in their biology, behavior, and prognosis and hence demand different treatment. They also respond differently to treatment. Some embryonal tumors presenting in infancy undergo spontaneous remission or maturation (e.g., Stage IVS neuroblastoma).