Anna Kelsey

Germline Mutations in SUFU Cause Gorlin Syndrome–Associated Childhood Medulloblastoma and Redefine the Risk Associated With PTCH1 Mutations

PURPOSE Heterozygous germline PTCH1 mutations are causative of Gorlin syndrome (naevoid basal cell carcinoma), but detection rates > 70% have rarely been reported. We aimed to define the causative mutations in individuals with Gorlin syndrome without PTCH1 mutations. METHODS We undertook exome sequencing on lymphocyte DNA from four unrelated individuals from families with Gorlin syndrome with no PTCH1 mutations found by Sanger sequencing, multiplex ligation-dependent probe amplification (MLPA), or RNA analysis. RESULTS A germline heterozygous nonsense mutation in SUFU was identified in one of four exomes. Sanger sequencing of SUFU in 23 additional PTCH1-negative Gorlin syndrome families identified a SUFU mutation in a second family. Copy-number analysis of SUFU by MLPA revealed a large heterozygous deletion in a third family. All three SUFU-positive families fulfilled diagnostic criteria for Gorlin syndrome, although none had odontogenic jaw keratocysts. Each SUFU-positive family included a single case of medulloblastoma, whereas only two (1.7%) of 115 individuals with Gorlin syndrome and a PTCH1 mutation developed medulloblastoma. CONCLUSION We demonstrate convincing evidence that SUFU mutations can cause classical Gorlin syndrome. Our study redefines the risk of medulloblastoma in Gorlin syndrome, dependent on the underlying causative gene. Previous reports have found a 5% risk of medulloblastoma in Gorlin syndrome. We found a < 2% risk in PTCH1 mutation-positive individuals, with a risk up to 20× higher in SUFU mutation-positive individuals. Our data suggest childhood brain magnetic resonance imaging surveillance is justified in SUFU-related, but not PTCH1-related, Gorlin syndrome.

Detection of the PAX3-FKHR fusion gene in paediatric rhabdomyosarcoma: a reproducible predictor of outcome?

Rhabdomyosarcoma has 2 major histological subtypes, embryonal and alveolar. Alveolar histology is associated with the fusion genes PAX3-FKHR and PAX7-FKHR. Definition of alveolar has been complicated by changes in terminology and subjectivity. It is currently unclear whether adverse clinical behaviour is better predicted by the presence of these fusion genes or by alveolar histology. We have determined the presence of the PAX3/7-FKHR fusion genes in 91 primary rhabdomyosarcoma tumours using a combination of classical cytogenetics, FISH and RT-PCR, with a view to determining the clinical characteristics of tumours with and without the characteristic translocations. There were 37 patients with t(2;13)/PAX3-FKHR, 8 with t(1;13) PAX7-FKHR and 46 with neither translocation. One or other of the characteristic translocations was found in 31/38 (82%) of alveolar cases. Univariate survival analysis revealed the presence of the translocation t(2;13)/PAX3-FKHR to be an adverse prognostic factor. With the difficulties in morphological diagnosis of alveolar rhabdomyosarcoma on increasingly used small needle biopsy specimens, these data suggest that molecular analysis for PAX3-FKHR will be a clinically useful tool in treatment stratification in the future. This hypothesis requires testing in a prospective study. Variant t(1;13)/PAX7-FKHR appears biologically different, occurring in younger patients with more localised disease.

Relationship Between MYCN Copy Number and Expression in Rhabdomyosarcomas and Correlation With Adverse Prognosis in the Alveolar Subtype

PURPOSE Amplification of the transcription factor MYCN is an important molecular diagnostic tool in stratifying treatment for neuroblastoma. Increased copy number and overexpression of MYCN in the pediatric cancer rhabdomyosarcoma has been described in a number of small studies with conflicting conclusions about its association with clinicopathologic characteristics. We aimed to study the phenomenon in the largest series to date. PATIENTS AND METHODS Using quantitative polymerase chain reaction, we measured MYCN copy number and expression levels in rhabdomyosarcoma samples from 113 and 92 individuals with a confirmed diagnosis of rhabdomyosarcoma, respectively. RESULTS Increased copy number of MYCN was found to be a feature of both the embryonal and alveolar subtypes. The copy number and expression levels were significantly greater in the alveolar subtype, although the range of expression in both subtypes spanned several orders of magnitude. MYCN copy number showed a significant correlation with expression in the alveolar subtype; this relationship between copy number and expression could be modeled as a logarithmic function. It is notable that relatively high expression frequently occurred in embryonal rhabdomyosarcoma without high copy number and that low expression was found in some cases with high copy number. In patients with alveolar rhabdomyosarcoma, overexpression (greater than median) or gain of genomic copies of MYCN were significantly associated with adverse outcome. CONCLUSION MYCN deregulation is a feature of rhabdomyosarcoma tumorigenesis, defines groups of patients with a poor prognosis, and is a potential target for novel therapies.

Randomized Comparison of Intensified Six-Drug Versus Standard Three-Drug Chemotherapy for High-Risk Nonmetastatic Rhabdomyosarcoma and Other Chemotherapy-Sensitive Childhood Soft Tissue Sarcomas: Long-Term Results From the International Society of Pediatric Oncology MMT95 Study

PURPOSE MMT95 was the fourth of a series of International Society of Pediatric Oncology (SIOP) collaborations for children with high-risk nonmetastatic soft tissue sarcoma (STS). The principal objective was to explore survival advantage for an intensified chemotherapy strategy in a randomized trial. PATIENTS AND METHODS From July 1995 to June 2003, 457 previously untreated patients with incompletely resected embryonal rhabdomyosarcoma (RMS), undifferentiated sarcoma, and soft tissue primitive neuroectodermal tumor at all sites except paratesticular, vagina, and uterus, or with alveolar RMS were randomly assigned to receive either ifosfamide, vincristine, and dactinomycin (IVA) or a six-drug combination (IVA plus carboplatin, epirubicin, and etoposide) both delivered over 27 weeks. Cumulative doses were as follows: ifosfamide 54 g/m(2) (both arms), epirubicin 450 mg/m(2), etoposide 1,350 mg/m(2) (six-drug regimen). Poor responders after three courses of IVA were to be switched to the other arm. Delivery of radiotherapy was determined according to site and/or response to chemotherapy with or without surgery. RESULTS Overall survival (OS) for all patients was 81% (95% CI, 77% to 84%) at 3 years. No significant difference in outcome in either OS or event-free survival was noted between the two arms (3-year OS: 82% [95% CI, 76% to 86%] for IVA and 80% [95% CI, 74% to 85%] for the six-drug arm). Toxicity was significantly greater (infection, myelosuppression, and mucositis) in the six-drug arm. Overall burden of local therapy was consistent with data from previous SIOP studies and showed no difference between the two chemotherapy regimens. CONCLUSION Intensification of chemotherapy for nonmetastatic RMS and other chemotherapy-sensitive STS provides no survival advantage or reduction in the intensity of local therapy and adds toxicity.

Non-metastatic unresected paediatric non-rhabdomyosarcoma soft tissue sarcomas: Results of a pooled analysis from United States and European groups

BACKGROUND Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) with initially unresected tumours represent a particular subset of patients with a poor outcome. Various international research groups pooled their data in a joint study in order to investigate prognostic variables and treatment modalities. METHODS The study population consisted of 304 patients <21 years old treated between 1980 and 2005 using a multimodality therapeutic strategy. RESULTS Synovial sarcoma and malignant peripheral nerve sheath tumour (MPNST) were the most frequent histotypes. Most patients received initial chemotherapy: major responses were recorded in 41% and minor in 16% of cases. Overall survival (OS) was 60.0% and 51.5% at 5 and 10 years, respectively, and it was significantly associated with patients age, histological subtype, tumour site and size, quality of delayed surgical resection, radiotherapy administration and response to induction chemotherapy. MPNST associated to neurofibromatosis type 1 was the tumour type with the worst rate of response to chemotherapy and the worst outcome. CONCLUSIONS In unresected NRSTS patients, radiotherapy and delayed surgery are of crucial importance. Patients who respond to chemotherapy have better chance of survival. However, given the relatively poor prognosis, research on intensive multimodal treatment approaches and novel strategies is warranted.

Prognostic classification of relapsing favorable histology Wilms tumor using cDNA microarray expression profiling and support vector machines

Treatment of Wilms tumor has a high success rate, with some 85% of patients achieving long‐term survival. However, late effects of treatment and management of relapse remain significant clinical problems. If accurate prognostic methods were available, effective risk‐adapted therapies could be tailored to individual patients at diagnosis. Few molecular prognostic markers for Wilms tumor are currently defined, though previous studies have linked allele loss on 1p or 16q, genomic gain of 1q, and overexpression from 1q with an increased risk of relapse. To identify specific patterns of gene expression that are predictive of relapse, we used high‐density (30 k) cDNA microarrays to analyze RNA samples from 27 favorable histology Wilms tumors taken from primary nephrectomies at the time of initial diagnosis. Thirteen of these tumors relapsed within 2 years. Genes differentially expressed between the relapsing and nonrelapsing tumor classes were identified by statistical scoring (t test). These genes encode proteins with diverse molecular functions, including transcription factors, developmental regulators, apoptotic factors, and signaling molecules. Use of a support vector machine classifier, feature selection, and test evaluation using cross‐validation led to identification of a generalizable expression signature, a small subset of genes whose expression potentially can be used to predict tumor outcome in new samples. Similar methods were used to identify genes that are differentially expressed between tumors with and without genomic 1q gain. This set of discriminators was highly enriched in genes on 1q, indicating close agreement between data obtained from expression profiling with data from genomic copy number analyses.

Synovial sarcoma in childhood and adolescence: A retrospective series of 77 patients registered by the Children's Cancer and Leukaemia Group between 1991 and 2006

The analysis of a contemporary multi‐centre series of synovial sarcoma in children and young people describes the clinical characteristics, examines the effect of known prognostic factors and looks at outcome with particular emphasis on a conservative approach to treatment of localised disease.

Allele loss at 16q defines poorer prognosis Wilms tumour irrespective of treatment approach in the UKW1-3 clinical trials: A Children's Cancer and Leukaemia Group (CCLG) study

Survival from Wilms tumour is excellent. Hence, better markers are required to restrict treatments causing late sequelae to those at highest risk of relapse. We investigated the prognostic significance of loss of heterozygosity (LOH) on 1p and 16q in 426 favourable histology Wilms tumours treated with either immediate nephrectomy (63%) or preoperative chemotherapy (37%). Four years RFS and OS were 84.6% and 92.0%, respectively. 10.3% tumours had LOH 1p, 14.6% LOH 16q, with 2.6% at both loci. In multivariate analysis, LOH 16q was associated with an increased risk of relapse (hazard ratio (HR) 2.69, 95%CI: 1.47-4.92) and death (HR 2.67, 95%CI: 1.17-6.06). LOH 1p showed no significant associations. These results were not influenced by treatment approach. LOH 16q is an adverse risk factor in favourable histology Wilms tumour, regardless of initial approach to therapy. Its relationship with histological risk groups defined after neo-adjuvant chemotherapy requires analysis in a larger series, and is the subject of the current SIOP WT 2001 trial.

Isolated intracranial Rosai-Dorfman disease mimicking meningioma in a child.

A 9-year-old boy presented with a 12-month history of headaches and recent grand mal seizures. Computed tomography and magnetic resonance imaging of the brain revealed an enhancing right frontal convexity lesion. The preoperative diagnosis was meningioma. However, histological examination was diagnostic of Rosai - Dorfman disease. Rosai - Dorfman disease confined to the intracranial compartment is very rare, of 34 reported cases only one presented in the first decade. Optimal treatment has not been established, but complete surgical resection alone seems effective and allows histological distinction from meningioma.

Synovial sarcoma in children and adolescents: the European pediatric Soft tissue sarcoma Study Group prospective trial (EpSSG NRSTS 2005)

BACKGROUND To report the results of the first European prospective nonrandomized trial dedicated to pediatric synovial sarcoma. PATIENTS AND METHODS From August 2005 to August 2012, 138 patients <21 years old with nonmetastatic synovial sarcoma were registered in 9 different countries (and 60 centers). Patients were treated with a multimodal therapy including ifosfamide-doxorubicin chemotherapy and radiotherapy, according to a risk stratification based on surgical stage, tumor size and site, and nodal involvement. RESULTS With a median follow-up of 52.1 months (range 13.8-104.4 months), event-free survival (EFS) was 81.9% and 80.7%, and overall survival (OS) was 97.2% and 90.7%, at 3 and 5 years, respectively. The only significant prognostic variable at univariate analysis was the risk group: 3-year EFS was 91.7% for low-risk, 91.2% for intermediate-risk, and 74.4% for high-risk cases. In 24 low-risk patients (completely resected tumor ≤5 cm in size) treated with surgery alone, there were two local relapses and no metastatic recurrences. Among 67 high-risk patients (unresected, or axial tumor or nodal involvement), 66 underwent surgery after neoadjuvant chemotherapy. Response to chemotherapy was 55.2%, including 22.4% cases with complete or major partial remissions, and 32.8% with minor partial remissions. CONCLUSION This study demonstrates that collaborative prospective studies on rare pediatric sarcomas are feasible even on a European scale, with excellent treatment compliance. The overall results of treatment were satisfactory, with higher survival rates than those previously published by pediatric groups. Nonetheless, larger, international projects are needed, based on a cooperative effort of pediatric and adult oncologists. CLINICAL TRIALS NUMBER European Union Drug Regulating Authorities Clinical Trials No. 2005-001139-31.