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In this Article, author Benedikt Brors was erroneously associated with affiliation number '8' (Department of Developmental Neurobiology, St Jude Children's Research Hospital, Memphis, Tennessee, USA); the author's two other affiliations (affiliations '3' and '7', both at the German Cancer Research Center (DKFZ)) were correct. This has been corrected online.
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Accurate pathological diagnosis is crucial for optimal management of patients with cancer. For the approximately 100 known tumour types of the central nervous system, standardization of the diagnostic process has been shown to be particularly challenging-with substantial inter-observer variability in the histopathological diagnosis of many tumour types. Here we present a comprehensive approach for the DNA methylation-based classification of central nervous system tumours across all entities and age groups, and demonstrate its application in a routine diagnostic setting. We show that the availability of this method may have a substantial impact on diagnostic precision compared to standard methods, resulting in a change of diagnosis in up to 12% of prospective cases. For broader accessibility, we have designed a free online classifier tool, the use of which does not require any additional onsite data processing. Our results provide a blueprint for the generation of machine-learning-based tumour classifiers across other cancer entities, with the potential to fundamentally transform tumour pathology.
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Neoplasias do Sistema Nervoso Central/diagnóstico , Neoplasias do Sistema Nervoso Central/genética , Metilação de DNA , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Sistema Nervoso Central/classificação , Neoplasias do Sistema Nervoso Central/patologia , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Aprendizado de Máquina não Supervisionado , Adulto JovemRESUMO
Pan-cancer analyses that examine commonalities and differences among various cancer types have emerged as a powerful way to obtain novel insights into cancer biology. Here we present a comprehensive analysis of genetic alterations in a pan-cancer cohort including 961 tumours from children, adolescents, and young adults, comprising 24 distinct molecular types of cancer. Using a standardized workflow, we identified marked differences in terms of mutation frequency and significantly mutated genes in comparison to previously analysed adult cancers. Genetic alterations in 149 putative cancer driver genes separate the tumours into two classes: small mutation and structural/copy-number variant (correlating with germline variants). Structural variants, hyperdiploidy, and chromothripsis are linked to TP53 mutation status and mutational signatures. Our data suggest that 7-8% of the children in this cohort carry an unambiguous predisposing germline variant and that nearly 50% of paediatric neoplasms harbour a potentially druggable event, which is highly relevant for the design of future clinical trials.
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Genoma Humano/genética , Genômica , Mutação/genética , Neoplasias/classificação , Neoplasias/genética , Adolescente , Adulto , Criança , Cromotripsia , Estudos de Coortes , Variações do Número de Cópias de DNA/genética , Diploide , Predisposição Genética para Doença/genética , Mutação em Linhagem Germinativa/genética , Humanos , Terapia de Alvo Molecular , Taxa de Mutação , Neoplasias/tratamento farmacológico , Proteína Supressora de Tumor p53/genética , Adulto JovemRESUMO
Reelin, a large extracellular protein, plays several critical roles in brain development and function. It is encoded by RELN, first identified as the gene disrupted in the reeler mouse, a classic neurological mutant exhibiting ataxia, tremors and a 'reeling' gait. In humans, biallelic variants in RELN have been associated with a recessive lissencephaly variant with cerebellar hypoplasia, which matches well with the homozygous mouse mutant that has abnormal cortical structure, small hippocampi and severe cerebellar hypoplasia. Despite the large size of the gene, only 11 individuals with RELN-related lissencephaly with cerebellar hypoplasia from six families have previously been reported. Heterozygous carriers in these families were briefly reported as unaffected, although putative loss-of-function variants are practically absent in the population (probability of loss of function intolerance = 1). Here we present data on seven individuals from four families with biallelic and 13 individuals from seven families with monoallelic (heterozygous) variants of RELN and frontotemporal or temporal-predominant lissencephaly variant. Some individuals with monoallelic variants have moderate frontotemporal lissencephaly, but with normal cerebellar structure and intellectual disability with severe behavioural dysfunction. However, one adult had abnormal MRI with normal intelligence and neurological profile. Thorough literature analysis supports a causal role for monoallelic RELN variants in four seemingly distinct phenotypes including frontotemporal lissencephaly, epilepsy, autism and probably schizophrenia. Notably, we observed a significantly higher proportion of loss-of-function variants in the biallelic compared to the monoallelic cohort, where the variant spectrum included missense and splice-site variants. We assessed the impact of two canonical splice-site variants observed as biallelic or monoallelic variants in individuals with moderately affected or normal cerebellum and demonstrated exon skipping causing in-frame loss of 46 or 52 amino acids in the central RELN domain. Previously reported functional studies demonstrated severe reduction in overall RELN secretion caused by heterozygous missense variants p.Cys539Arg and p.Arg3207Cys associated with lissencephaly suggesting a dominant-negative effect. We conclude that biallelic variants resulting in complete absence of RELN expression are associated with a consistent and severe phenotype that includes cerebellar hypoplasia. However, reduced expression of RELN remains sufficient to maintain nearly normal cerebellar structure. Monoallelic variants are associated with incomplete penetrance and variable expressivity even within the same family and may have dominant-negative effects. Reduced RELN secretion in heterozygous individuals affects only cortical structure whereas the cerebellum remains intact. Our data expand the spectrum of RELN-related neurodevelopmental disorders ranging from lethal brain malformations to adult phenotypes with normal brain imaging.
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Lisencefalia , Proteína Reelina , Adulto , Cerebelo/anormalidades , Criança , Deficiências do Desenvolvimento/genética , Humanos , Lisencefalia/complicações , Mutação , Malformações do Sistema Nervoso , Proteína Reelina/genéticaRESUMO
BACKGROUND: Eye-preserving therapy in retinoblastoma comprises systemic chemotherapy, but studies analyzing the efficacy of different chemotherapy regimens are scarce. METHODS: The efficacy and side effects of two different eye-preserving chemotherapy regimens containing either vincristine, etoposide, and carboplatin (VEC) or cyclophosphamide, vincristine, etoposide, and carboplatin (CyVEC) were compared in a prospective non-interventional observational study including children diagnosed with retinoblastoma between 2013 and 2019 in Germany and Austria. Event-free eye survival (EFES) and overall eye survival (OES) of all 164 eyes treated with both regimens and risk factors were investigated. RESULTS: The EFES after VEC (2-year EFES 72.3%) was higher than after CyVEC (2-year EFES 50.4%) (plogrank < .001). The OES did not differ significantly between the two treatment groups (plogrank = .77; 2-year OES VEC: 82.1% vs. CyVEC: 84.8%). Advanced International Classification of Retinoblastoma (ICRB) group was prognostic for a lower EFES (plogrank < .0001; 2-year EFES ICRB A/B/C 71.3% vs. ICRB D/E 43.0%) and OES (plogrank < .0001; 2-year OES ICRB A/B/C 93.1% vs. ICRB D/E 61.5%). The multivariate analysis showed that age at diagnosis older than 12 months and ICRB A/B/C were associated with better EFES. No second malignancies or ototoxicities were reported after a follow-up of median 3.1 years after diagnosis of retinoblastoma (range 0.1-6.9 years). CONCLUSIONS: Despite omitting cyclophosphamide, the EFES was higher after VEC chemotherapy that contains higher doses of carboplatin compared to CyVEC. The major risk factor for enucleation was advanced ICRB tumor grouping. Randomized clinical trials on efficacy and side effects of eye-preserving chemotherapy are required to tailor treatment protocols for retinoblastoma patients.
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Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Neoplasias da Retina , Retinoblastoma , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carboplatina , Criança , Ciclofosfamida , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/tratamento farmacológico , Etoposídeo , Enucleação Ocular , Humanos , Estudos Prospectivos , Neoplasias da Retina/tratamento farmacológico , Neoplasias da Retina/patologia , Retinoblastoma/tratamento farmacológico , Retinoblastoma/patologia , VincristinaRESUMO
Tumors of the pineal region comprise several different entities with distinct clinical and histopathological features. Whereas some entities predominantly affect adults, pineoblastoma (PB) constitutes a highly aggressive malignancy of childhood with a poor outcome. PBs mainly arise sporadically, but may also occur in the context of cancer predisposition syndromes including DICER1 and RB1 germline mutation. With this study, we investigate clinico-pathological subgroups of pineal tumors and further characterize their biological features. We performed genome-wide DNA methylation analysis in 195 tumors of the pineal region and 20 normal pineal gland controls. Copy-number profiles were obtained from DNA methylation data; gene panel sequencing was added for 93 tumors and analysis was further complemented by miRNA sequencing for 22 tumor samples. Unsupervised clustering based on DNA methylation profiling separated known subgroups, like pineocytoma, pineal parenchymal tumor of intermediate differentiation, papillary tumor of the pineal region and PB, and further distinct subtypes within these groups, including three subtypes within the core PB subgroup. The novel molecular subgroup Pin-RB includes cases of trilateral retinoblastoma as well as sporadic pineal tumors with RB1 alterations, and displays similarities with retinoblastoma. Distinct clinical associations discriminate the second novel molecular subgroup PB-MYC from other PB cases. Alterations within the miRNA processing pathway (affecting DROSHA, DGCR8 or DICER1) are found in about two thirds of cases in the three core PB subtypes. Methylation profiling revealed biologically distinct groups of pineal tumors with specific clinical and molecular features. Our findings provide a foundation for further clinical as well as molecular and functional characterization of PB and other pineal tumors, including the role of miRNA processing defects in oncogenesis.
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Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Glândula Pineal , Pinealoma/genética , Pinealoma/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/metabolismo , Estudos de Casos e Controles , Criança , Metilação de DNA , Feminino , Humanos , Masculino , MicroRNAs , Pessoa de Meia-Idade , Mutação/genética , Pinealoma/metabolismo , Adulto JovemRESUMO
PURPOSE: Monosomy 3 (M3) in uveal melanoma (UM) obtained after enucleation is significantly associated with metastatic death. With improved biopsy techniques, samples from patients treated with eye-preserving methods have become available. As the choice of treatment depends on tumour size, patients treated with eye-preserving brachytherapy tend to have smaller tumours. It has to be determined if M3 is a valid marker for prognosis of these patients. METHODS: Follow-up and clinical data were collected from a total of 451 UM patients: 291 patients were treated by brachytherapy. Tumour tissue was sampled by transretinal biopsy using the 23-gauge Essen biopsy forceps prior to therapy in 114 of them. Chromosome 3 status was determined by microsatellite analysis. Data were compared to those from 160 patients treated by enucleation. RESULTS: Chromosome 3 status correlates significantly with disease-related survival in both patient groups. The proportion of tumours with M3 is lower in the brachytherapy group compared to patients treated with enucleation (25/77 32% and 102/144 71%, respectively). CONCLUSIONS: M3 is a valid marker for poor prognosis in uveal melanoma later treated by brachytherapy. The higher proportion of D3 tumours might explain, at least in part, the more favourable prognosis of patients treated by brachytherapy.
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Cromossomos Humanos Par 3/genética , Melanoma/genética , Monossomia/genética , Prognóstico , Neoplasias Uveais/genética , Adulto , Idoso , Biomarcadores Tumorais , Biópsia , Braquiterapia/efeitos adversos , Feminino , Humanos , Masculino , Melanoma/patologia , Pessoa de Meia-Idade , Neoplasias Uveais/patologiaRESUMO
Heritable retinoblastoma can rarely be associated with a midline intracranial neuroblastic tumor, referred to as trilateral retinoblastoma. We present an unusual midline brain tumor in an infant that was identified as ectopic retinoblastoma by histopathology, DNA methylation analysis, and molecular genetic detection of biallelic somatic inactivation of the RB1 gene. There was no ocular involvement, and germline mutation was excluded. In this nonresectable tumor, treatment with systemic chemotherapy including high-dose therapy with autologous stem cell transplantation, but without definite local therapy, resulted in long-lasting tumor control.
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Neoplasias Encefálicas/patologia , Predisposição Genética para Doença , Mutação , Neoplasias da Retina/patologia , Proteínas de Ligação a Retinoblastoma/genética , Retinoblastoma/patologia , Ubiquitina-Proteína Ligases/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Humanos , Lactente , Masculino , Prognóstico , Neoplasias da Retina/genética , Neoplasias da Retina/terapia , Retinoblastoma/genética , Retinoblastoma/terapia , Transplante de Células-Tronco , Transplante AutólogoRESUMO
We report three individuals with a cranioskeletal malformation syndrome that we define as acrofacial dysostosis, Cincinnati type. Each individual has a heterozygous mutation in POLR1A, which encodes a core component of RNA polymerase 1. All three individuals exhibit varying degrees of mandibulofacial dysostosis, and two additionally have limb anomalies. Consistent with this observation, we discovered that polr1a mutant zebrafish exhibited cranioskeletal anomalies mimicking the human phenotype. polr1a loss of function led to perturbed ribosome biogenesis and p53-dependent cell death, resulting in a deficiency of neural-crest-derived skeletal precursor cells and consequently craniofacial anomalies. Our findings expand the genotypic and phenotypic heterogeneity of congenital acrofacial disorders caused by disruption of ribosome biogenesis.
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Deformidades Congênitas dos Membros/genética , Disostose Mandibulofacial/genética , RNA Polimerase I/genética , Ribossomos/genética , Animais , Morte Celular/genética , Genótipo , Humanos , Deformidades Congênitas dos Membros/fisiopatologia , Disostose Mandibulofacial/fisiopatologia , Mutação , Crista Neural/crescimento & desenvolvimento , Crista Neural/patologia , Ribossomos/patologia , Peixe-ZebraRESUMO
Mutations in components of the major spliceosome have been described in disorders with craniofacial anomalies, e.g., Nager syndrome and mandibulofacial dysostosis type Guion-Almeida. The U5 spliceosomal complex of eight highly conserved proteins is critical for pre-mRNA splicing. We identified biallelic mutations in TXNL4A, a member of this complex, in individuals with Burn-McKeown syndrome (BMKS). This rare condition is characterized by bilateral choanal atresia, hearing loss, cleft lip and/or palate, and other craniofacial dysmorphisms. Mutations were found in 9 of 11 affected families. In 8 families, affected individuals carried a rare loss-of-function mutation (nonsense, frameshift, or microdeletion) on one allele and a low-frequency 34 bp deletion (allele frequency 0.76%) in the core promoter region on the other allele. In a single highly consanguineous family, formerly diagnosed as oculo-oto-facial dysplasia, the four affected individuals were homozygous for a 34 bp promoter deletion, which differed from the promoter deletion in the other families. Reporter gene and in vivo assays showed that the promoter deletions led to reduced expression of TXNL4A. Depletion of TXNL4A (Dib1) in yeast demonstrated reduced assembly of the tri-snRNP complex. Our results indicate that BMKS is an autosomal-recessive condition, which is frequently caused by compound heterozygosity of low-frequency promoter deletions in combination with very rare loss-of-function mutations.
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Atresia das Cóanas/genética , Surdez/congênito , Deleção de Genes , Cardiopatias Congênitas/genética , Regiões Promotoras Genéticas/genética , Ribonucleoproteína Nuclear Pequena U5/genética , Spliceossomos/genética , Alelos , Pré-Escolar , Atresia das Cóanas/diagnóstico , Surdez/diagnóstico , Surdez/genética , Exossomos/genética , Fácies , Feminino , Perfilação da Expressão Gênica , Frequência do Gene , Genes Reporter , Cardiopatias Congênitas/diagnóstico , Heterozigoto , Homozigoto , Humanos , Masculino , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Linhagem , Fenótipo , Ribonucleoproteína Nuclear Pequena U5/metabolismo , Análise de Sequência de DNA , Spliceossomos/metabolismoRESUMO
Heritable predisposition is an important cause of cancer in children and adolescents. Although a large number of cancer predisposition genes and their associated syndromes and malignancies have already been described, it appears likely that there are more pediatric cancer patients in whom heritable cancer predisposition syndromes have yet to be recognized. In a consensus meeting in the beginning of 2016, we convened experts in Human Genetics and Pediatric Hematology/Oncology to review the available data, to categorize the large amount of information, and to develop recommendations regarding when a cancer predisposition syndrome should be suspected in a young oncology patient. This review summarizes the current knowledge of cancer predisposition syndromes in pediatric oncology and provides essential information on clinical situations in which a childhood cancer predisposition syndrome should be suspected.
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Predisposição Genética para Doença , Neoplasias Hematológicas/diagnóstico , Mutação , Proteínas de Neoplasias/genética , Neoplasias/diagnóstico , Adolescente , Criança , Grupos Focais/métodos , Expressão Gênica , Aconselhamento Genético/ética , Testes Genéticos/métodos , Genética Médica/história , Genética Médica/instrumentação , Genética Médica/métodos , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/patologia , História do Século XXI , Humanos , Neoplasias/genética , Neoplasias/patologia , Sociedades Médicas/história , SíndromeRESUMO
BACKGROUND: Survivors of heritable retinoblastoma carry a high risk to develop second cancers. Eye-preserving radiotherapy raises this risk, while the impact of chemotherapy remains less defined. PROCEDURE: This population-based study characterizes the impact of all treatment modalities on second cancers incidence and type after retinoblastoma treatment in Germany. Data on second cancer incidence in 648 patients with heritable retinoblastoma treated between 1940 and 2008 at the German national reference center for retinoblastoma were analyzed to identify associations with treatment. RESULTS: The cumulative incidence ratio (per 1,000 person years) of second cancers was 8.6 (95% confidence interval 7.0-10.4). Second cancer incidence was influenced by type of retinoblastoma treatment but not by the year of diagnosis or by sex. Radiotherapy and systemic chemotherapy increased the incidence of second cancers (by 3.0- and 1.8-fold, respectively). While radiotherapy was specifically associated with second cancers arising within the periorbital region in the previously irradiated field, chemotherapy was the strongest risk factor for second cancers in other localizations. Soft tissue sarcomas and osteosarcomas were the most prevalent second cancers (standardized incidence ratio 179.35 compared to the German population). CONCLUSIONS: Second cancers remain a major concern in heritable retinoblastoma survivors. Consistent with previous reports, radiotherapy increased second cancer incidence and influenced type and localization. However, chemotherapy was the strongest risk factor for second malignancies outside the periorbital region. Our results provide screening priorities during life-long oncological follow-up based on the curative therapy the patient has received and emphasize the need for less-detrimental therapies for children with heritable retinoblastoma.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Quimiorradioterapia/mortalidade , Segunda Neoplasia Primária/epidemiologia , Neoplasias da Retina/terapia , Retinoblastoma/terapia , Sobreviventes , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Seguimentos , Alemanha/epidemiologia , Humanos , Incidência , Lactente , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Neoplasias da Retina/patologia , Retinoblastoma/patologia , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida , Adulto JovemRESUMO
BACKGROUND: Uveal melanoma patients with a poor prognosis can be detected through genetic analysis of the tumor, which has a very high sensitivity. A large number of patients with uveal melanoma decide to receive information about their individual risk and therefore routine prognostic genetic testing is being carried out on a growing number of patients. It is obvious that a positive prediction for recidivism in the future will emotionally burden the respective patients, but research on the psychosocial impact of this innovative method is lacking. The aim of the current study is therefore to investigate the psychosocial impact (psychological distress and quality of life) of prognostic genetic testing in patients with uveal melanoma. DESIGN AND METHODS: This study is a non-randomized controlled prospective clinical observational trial. Subjects are patients with uveal melanoma, in whom genetic testing is possible. Patients who consent to genetic testing are allocated to the intervention group and patients who refuse genetic testing form the observational group. Both groups receive cancer therapy and psycho-oncological intervention when needed. The psychosocial impact of prognostic testing is investigated with the following variables: resilience, social support, fear of tumor progression, depression, general distress, cancer-specific and general health-related quality of life, attitude towards genetic testing, estimation of the perceived risk of metastasis, utilization and satisfaction with psycho-oncological crisis intervention, and sociodemographic data. Data are assessed preoperatively (at initial admission in the clinic) and postoperatively (at discharge from hospital after surgery, 6-12 weeks, 6 and 12 months after initial admission). Genetic test results are communicated 6-12 weeks after initial admission to the clinic. DISCUSSION: We created optimal conditions for investigation of the psychosocial impact of prognostic genetic testing. This study will provide information on the course of disease and psychosocial outcomes after prognostic genetic testing. We expect that empirical data from our study will give a scientific basis for medico-ethical considerations.
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Testes Genéticos/métodos , Melanoma/genética , Melanoma/psicologia , Estresse Psicológico/etiologia , Neoplasias Uveais/genética , Neoplasias Uveais/psicologia , Idoso , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Qualidade de Vida/psicologiaRESUMO
Mandibulofacial dysostosis with microcephaly (MFDM) is a rare sporadic syndrome comprising craniofacial malformations, microcephaly, developmental delay, and a recognizable dysmorphic appearance. Major sequelae, including choanal atresia, sensorineural hearing loss, and cleft palate, each occur in a significant proportion of affected individuals. We present detailed clinical findings in 12 unrelated individuals with MFDM; these 12 individuals compose the largest reported cohort to date. To define the etiology of MFDM, we employed whole-exome sequencing of four unrelated affected individuals and identified heterozygous mutations or deletions of EFTUD2 in all four. Validation studies of eight additional individuals with MFDM demonstrated causative EFTUD2 mutations in all affected individuals tested. A range of EFTUD2-mutation types, including null alleles and frameshifts, is seen in MFDM, consistent with haploinsufficiency; segregation is de novo in all cases assessed to date. U5-116kD, the protein encoded by EFTUD2, is a highly conserved spliceosomal GTPase with a central regulatory role in catalytic splicing and post-splicing-complex disassembly. MFDM is the first multiple-malformation syndrome attributed to a defect of the major spliceosome. Our findings significantly extend the range of reported spliceosomal phenotypes in humans and pave the way for further investigation in related conditions such as Treacher Collins syndrome.
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GTP Fosfo-Hidrolases/genética , Haploinsuficiência/genética , Disostose Mandibulofacial/genética , Microcefalia/genética , Ribonucleoproteína Nuclear Pequena U5/genética , Anormalidades Múltiplas/genética , Alelos , Sequência de Aminoácidos , Criança , Pré-Escolar , Estudos de Coortes , Exoma , Feminino , Humanos , Lactente , Masculino , Dados de Sequência Molecular , Mutação/genética , Estrutura Terciária de Proteína/genética , Splicing de RNA/genética , Spliceossomos/genéticaRESUMO
BACKGROUND: Children with retinoblastoma carry a high risk to develop second primary malignancies in childhood and adolescence. This study characterizes the type of pediatric second primary malignancies after retinoblastoma treatment and investigates the impact of different treatment strategies and prognostic factors at presentation. PROCEDURE: All national patients treated for retinoblastoma at the German referral center with a current age of 6-27 years were invited to participate in a study to characterize late effects. RESULTS: Data on pediatric second primary malignancies were recorded from 488 patients. Ten developed a malignancy before the age of 18 years. For children with heterozygous oncogenic RB1 alteration (heritable retinoblastoma), the cumulative incidence to develop a second malignancy at the age of 10 years was 5.2% (95% CI 1.7; 8.7%). This results in an elevated risk for sarcoma (n = 4) (SIR 147.98; 95% CI 39.81; 378.87) and leukemia (n = 4) (SIR 41.38; 95% CI 11.13; 105.95). Neither the functional type of the RB1 alteration nor its origin showed a significant impact. Treatment modality influenced incidence, latency, and type of malignancy. Previous radiotherapy increased the risk for solid tumors and 3 of 91 children developed acute leukemia after chemotherapy. However, 2 of 10 malignancies were diagnosed in patients with heritable retinoblastoma but without previous chemotherapy or external beam radiotherapy. CONCLUSIONS: Screening for second primary malignancy is an important part of pediatric oncological follow-up in patients with heritable retinoblastoma. For patients with sporadic unilateral retinoblastoma, genetic information influences treatment decisions and allows tailoring of follow-up schedules.
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Segunda Neoplasia Primária/epidemiologia , Neoplasias da Retina/terapia , Retinoblastoma/terapia , Adolescente , Adulto , Antineoplásicos/efeitos adversos , Criança , Estudos de Coortes , Feminino , Humanos , Incidência , Estimativa de Kaplan-Meier , Masculino , Radioterapia/efeitos adversos , Adulto JovemRESUMO
PURPOSE: Treacher Collins syndrome is a mandibulofacial dysostosis caused by mutations in genes involved in ribosome biogenesis and synthesis. TCOF1 mutations are observed in ~80% of the patients and are inherited in an autosomal dominant manner. Recently, two other genes have been reported in <2% of patients--POLR1D in patients with autosomal dominant inheritance, and POLR1C in patients with autosomal recessive inheritance. METHODS: We performed direct sequencing of TCOF1, POLR1C, and POLR1D in two unrelated consanguineous families. RESULTS: The four affected children shared the same homozygous mutation in POLR1D (c.163C>G, p.Leu55Val). This mutation is localized in a region encoding the dimerization domain of the RNA polymerase. It is supposed that this mutation impairs RNA polymerase, resulting in a lower amount of mature dimeric ribosomes. A functional analysis of the transcripts of TCOF1 by real-time quantitative reverse transcription-polymerase chain reaction was performed in the first family, demonstrating a 50% reduction in the index case, compatible with this hypothesis. CONCLUSION: This is the first report of POLR1D mutation being responsible for an autosomal recessive inherited Treacher Collins syndrome. These results reinforce the concept of genetic heterogeneity of Treacher Collins syndrome and underline the importance of combining clinical expertise and familial molecular analyses for appropriate genetic counseling.
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RNA Polimerases Dirigidas por DNA/genética , Genes Recessivos , Disostose Mandibulofacial/diagnóstico , Disostose Mandibulofacial/genética , Mutação , Proteínas Nucleares/genética , Fosfoproteínas/genética , RNA Mensageiro/genética , Adulto , Substituição de Aminoácidos , Criança , Pré-Escolar , Análise Mutacional de DNA , Fácies , Feminino , Regulação da Expressão Gênica , Estudos de Associação Genética , Loci Gênicos , Haplótipos , Homozigoto , Humanos , FenótipoRESUMO
Heritable retinoblastoma is caused by oncogenic mutations in the RB1 tumor suppressor gene. Identification of these mutations in patients is important for genetic counseling and clinical management of relatives at risk. In order to lower analytical efforts, we designed a stepwise mutation detection strategy that was adapted to the spectrum of oncogenic RB1 gene mutations. We applied this strategy on 20 unrelated patients with familial and/or de novo bilateral retinoblastoma from Tunisia. In 19 (95%) patients, we detected oncogenic mutations including base substitutions, small length mutations, and large deletions. Further analyses on the origin of the mutations showed mutational mosaicism in one unilaterally affected father of a bilateral proband and incomplete penetrance in two mothers. In a large family with several retinoblastoma patients, the mutation identified in the index patient was also detected in several non-penetrant relatives. RNA analyses showed that this mutation results in an in-frame loss of exon 9. In summary, our strategy can serve as a model for RB1 mutation identification with high analytical sensitivity. Our results point out that genetic testing is needed to reveal or exclude incomplete penetrance specifically in parents of patients with sporadic disease.
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DNA de Neoplasias/genética , Família , Genes do Retinoblastoma/genética , Testes Genéticos/economia , Mutação , Linhagem , Retinoblastoma/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Análise Mutacional de DNA , Éxons , Feminino , Testes Genéticos/métodos , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real , Neoplasias da Retina/diagnóstico , Neoplasias da Retina/epidemiologia , Neoplasias da Retina/genética , Retinoblastoma/diagnóstico , Retinoblastoma/epidemiologia , Proteína do Retinoblastoma/genética , Proteína do Retinoblastoma/metabolismo , Fatores de Risco , Tunísia/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Retinoblastoma is the childhood retinal cancer that defined tumour-suppressor genes. Previous work shows that mutation of both alleles of the RB1 retinoblastoma suppressor gene initiates disease. We aimed to characterise non-familial retinoblastoma tumours with no detectable RB1 mutations. METHODS: Of 1068 unilateral non-familial retinoblastoma tumours, we compared those with no evidence of RB1 mutations (RB1(+/+)) with tumours carrying a mutation in both alleles (RB1(-/-)). We analysed genomic copy number, RB1 gene expression and protein function, retinal gene expression, histological features, and clinical data. FINDINGS: No RB1 mutations (RB1(+/+)) were reported in 29 (2·7%) of 1068 unilateral retinoblastoma tumours. 15 of the 29 RB1(+/+) tumours had high-level MYCN oncogene amplification (28-121 copies; RB1(+/+)MYCN(A)), whereas none of 93 RB1(-/-) primary tumours tested showed MYCN amplification (p<0·0001). RB1(+/+)MYCN(A) tumours expressed functional RB1 protein, had fewer overall genomic copy-number changes in genes characteristic of retinoblastoma than did RB1(-/-) tumours, and showed distinct aggressive histological features. MYCN amplification was the sole copy-number change in one RB1(+/+)MYCN(A) retinoblastoma. One additional MYCN(A) tumour was discovered after the initial frequencies were determined, and this is included in further analyses. Median age at diagnosis of the 17 children with RB1(+/+)MYCN(A) tumours was 4·5 months (IQR 3·5-10), compared with 24 months (15-37) for 79 children with non-familial unilateral RB1(-/-) retinoblastoma. INTERPRETATION: Amplification of the MYCN oncogene might initiate retinoblastoma in the presence of non-mutated RB1 genes. These unilateral RB1(+/+)MYCN(A) retinoblastomas are characterised by distinct histological features, only a few of the genomic copy-number changes that are characteristic of retinoblastoma, and very early age of diagnosis. FUNDING: National Cancer Institute-National Institutes of Health, Canadian Institutes of Health Research, German Research Foundation, Canadian Retinoblastoma Society, Hyland Foundation, Toronto Netralaya and Doctors Lions Clubs, Ontario Ministry of Health and Long Term Care, UK-Essen, and Foundations Avanti-STR and KiKa.
Assuntos
Dosagem de Genes , Proteínas Nucleares , Proteínas Oncogênicas , Proteína do Retinoblastoma , Retinoblastoma , Alelos , Linhagem Celular Tumoral , Criança , Pré-Escolar , Feminino , Amplificação de Genes , Regulação Neoplásica da Expressão Gênica , Genoma Humano , Humanos , Lactente , Mutação , Proteína Proto-Oncogênica N-Myc , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Polimorfismo de Nucleotídeo Único , Retinoblastoma/genética , Retinoblastoma/metabolismo , Retinoblastoma/patologia , Proteína do Retinoblastoma/genética , Proteína do Retinoblastoma/metabolismoRESUMO
Retinoblastoma is the most common eye cancer in children. It is caused by pathogenic alterations of both alleles of the tumor suppressor gene RB1. In heritable retinoblastoma, a constitutional RB1 variant predisposes the cells to tumor formation, and loss of the other allele is a prerequisite for the development of retinoblastoma. Heritable retinoblastoma is inherited in an autosomal dominant manner; however, the majority of cases are the result of a de novo pathogenic RB1 variant. Penetrance is usually high (>90%), but with marked inter-familial variability. In some families, penetrance is incomplete and family members who develop tumors tend to remain unilaterally affected. Moreover, some families with low penetrance also show a parent-of-origin effect. We describe a patient with unilateral retinoblastoma caused by a previously unreported likely pathogenic RB1 variant (c.1199T>C) that disrupts a highly conserved amino acid residue within the A-box functional domain. Segregation analysis showed that the variant had unusually low penetrance as nine non-affected family members carried the same variant. We emphasize the use of genetic analysis on tumor DNA for classifying the RB1 variant, and underline the challenges in clinical management and counseling of families carrying the specific RB1 variant.