[Show abstract][Hide abstract] ABSTRACT: The Sonic Hedgehog (SHH) signaling pathway plays an important role in neural crest cell fate during embryonic development and has been implicated in the progression of multiple cancers that include neuroblastoma, a neural crest cell-derived disease. While most of the SHH signaling is mediated by the well-described canonical pathway leading to the activation of Smoothened and Gli, it has recently been shown that cell-adhesion molecule-related/downregulated by oncogenes (CDON) serves as a receptor for SHH and contributes to SHH-induced signaling. CDON has also been recently described as a dependence receptor, triggering apoptosis in the absence of SHH. This CDON proapoptotic activity has been suggested to constrain tumor progression.
JNCI Journal of the National Cancer Institute 11/2014; 106(11). · 15.16 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The SWI/SNF complexes, initially identified in yeast 20 years ago, are a family of multi-subunit complexes that use the energy of adenosine triphosphate (ATP) hydrolysis to remodel nucleosomes. Chromatin remodeling processes mediated by the SWI/SNF complexes are critical to the modulation of gene expression across a variety of cellular processes, including stemness, differentiation, and proliferation. The first evidence of the involvement of these complexes in carcinogenesis was provided by the identification of biallelic, truncating mutations of the SMARCB1 gene in malignant rhabdoid tumors, a highly aggressive childhood cancer. Subsequently, genome-wide sequencing technologies have identified mutations in genes encoding different subunits of the SWI/SNF complexes in a large number of tumors. SWI/SNF mutations, and the subsequent abnormal function of SWI/SNF complexes, are among the most frequent gene alterations in cancer. The mechanisms by which perturbation of the SWI/SNF complexes promote oncogenesis are not fully elucidated; however, alterations of SWI/SNF genes obviously play a major part in cancer development, progression, and/or resistance to therapy. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease Volume 10 is January 24, 2015. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.
Annual Review of Pathology Mechanisms of Disease 10/2014; · 22.13 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose: To optimize neuroblastoma treatment stratification, we aimed at developing a novel risk estimation system by integrating gene expression-based classification and established prognostic markers. Material and Methods: Gene expression profiles were generated from 709 neuroblastoma specimens using customized 4x44K microarrays. Classification models were built using 75 tumors with contrasting courses of disease. Validation was performed in an independent test set (n=634) by Kaplan-Meier estimates and Cox regression analyses. Results: The best-performing classifier predicted patient outcome with an accuracy of 0.95 (sensitivity 0.93, specificity 0.97) in the validation cohort. The highest potential clinical value of this predictor was observed for current low-risk patients (LR: 5-year EFS 0.84±0.02 vs 0.29±0.10; 5-year OS 0.99±0.01vs 0.76±0.11; both p<0.001) and intermediate-risk patients (IR: 5-year EFS 0.88±0.06 vs 0.41±0.10; 5-year OS 1.0 vs 0.70±0.09; both p<0.001). In multivariate Cox regression models for LR/IR patients the classifier outperformed risk assessment of the current German trial NB2004 (EFS: HR 5.07, 95%-CI 3.20-8.02, OS: HR 25.54, 95%-CI 8.40-77.66; both p<0.001). Based on these findings, we propose to integrate the classifier into a revised risk stratification system for LR/IR patients. According to this system, we identified novel subgroups with poor outcome (5-year EFS 0.19±0.08; 5-year OS 0.59±0.1), for whom we propose intensified treatment, and with beneficial outcome (5-year EFS 0.87±0.05; 5-year OS 1.0), who may benefit from treatment de-escalation. Conclusion: Combination of gene expression-based classification and established prognostic markers improves risk estimation of LR/IR neuroblastoma patients. We propose to implement our revised treatment stratification system in a prospective clinical trial.
Clinical cancer research : an official journal of the American Association for Cancer Research. 09/2014;
[Show abstract][Hide abstract] ABSTRACT: Ewing sarcoma is a primary bone tumor initiated by EWSR1–ETS gene fusions. To identify secondary genetic lesions that contribute to tumor progression, we performed wholegenome sequencing of 112 Ewing sarcoma samples and matched germline DNA. Overall, Ewing sarcoma tumors had relatively few single-nucleotide variants, indels, structural variants and copy-number alterations. Apart from whole chromosome arm copy-number changes, the most common somatic mutations were detected in STAG2 (17%), CDKN2A (12%), TP53 (7%), EZH2, BCOR, and ZMYM3 (2.7% each). Strikingly, STAG2 mutations and CDKN2A deletions were mutually exclusive, as confirmed in Ewing sarcoma cell lines. In an expanded cohort of 299 patients with clinical data, we discovered that STAG2 and TP53 mutations are often concurrent and are associated with poor outcome. Finally, we detected subclonal STAG2 mutations in diagnostic tumors and expansion of STAG2 immuno-negative ncells in relapsed tumors as compared with matched diagnostic samples.
[Show abstract][Hide abstract] ABSTRACT: Neuroblastoma (NB) is an embryonal tumor of the sympathetic nervous system which accounts for 8–10% of pediatric cancers. It is characterized by a broad spectrum of clinical behaviors from spontaneous regression to fatal outcome despite aggressive therapies. Considerable progress has been made recently in the germline and somatic genetic characterization of patients and tumors. Indeed, predisposition genes that account for a significant proportion of familial and syndromic cases have been identified and genome-wide association studies have retrieved a number of susceptibility loci. In addition, genome-wide sequencing, copy-number and expression studies have been conducted on tumors and have detected important gene modifications, profiles and signatures that have strong implications for the therapeutic stratification of patients. The identification of major players in NB oncogenesis, including MYCN, ALK, PHOX2B and LIN28B, has enabled the development of new animal models. Our review focuses on these recent advances, on the insights they provide on the mechanisms involved in NB development and their applications for the clinical management of patients.
International Journal of Cancer 08/2014; · 6.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In neuroblastoma, the ALK receptor tyrosine kinase is activated by point mutations. We investigated the potential role of ALK mutations in neuroblastoma clonal evolution.
Journal of Clinical Oncology 07/2014; · 17.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Somatically acquired genomic alterations with MYCN amplification (MNA) are key features of neuroblastoma (NB), the most common extra-cranial malignant tumour of childhood. Little is known about the frequency, clinical characteristics and outcome of NBs harbouring genomic amplification(s) distinct from MYCN.
PLoS ONE 07/2014; 9(7):e101990. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The anaplastic lymphoma kinase (ALK) gene is overexpressed, mutated or amplified in most neuroblastoma (NB), a pediatric neural crest-derived embryonal tumor. The two most frequent mutations, ALK-F1174L and ALK-R1275Q, contribute to NB tumorigenesis in mouse models, and cooperate with MYCN in the oncogenic process. However, the precise role of activating ALK mutations or ALK-wt overexpression in NB tumor initiation needs further clarification. Human ALK-wt, ALK-F1174L, or ALK-R1275Q were stably expressed in murine neural crest progenitor cells (NCPC), MONC-1 or JoMa1, immortalized with v-Myc or Tamoxifen-inducible Myc-ERT, respectively. While orthotopic implantations of MONC-1 parental cells in nude mice generated various tumor types, such as NB, osteo/chondrosarcoma, and undifferentiated tumors, due to v-Myc oncogenic activity, MONC-1-ALK-F1174L cells only produced undifferentiated tumors. Furthermore, our data represent the first demonstration of ALK-wt transforming capacity, as ALK-wt expression in JoMa1 cells, likewise ALK-F1174L, or ALK-R1275Q, in absence of exogenous Myc-ERT activity, was sufficient to induce the formation of aggressive and undifferentiated neural crest cell-derived tumors, but not to drive NB development. Interestingly, JoMa1-ALK tumors and their derived cell lines upregulated Myc endogenous expression, resulting from ALK activation, and both ALK and Myc activities were necessary to confer tumorigenic properties on tumor-derived JoMa1 cells in vitro.
[Show abstract][Hide abstract] ABSTRACT: Pure invasive micropapillary carcinoma (IMPC) is a special type of breast carcinoma characterized by clusters of cells presenting polarity abnormalities. The biological alterations underlying this pattern remain unknown.
Breast cancer research: BCR 05/2014; 16(3):R46. · 5.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The ALK (Anaplastic Lymphoma Kinase) gene encodes a tyrosine kinase receptor preferentially expressed in the central and peripheral nervous systems. A syndromic presentation associating congenital neuroblastoma with severe encephalopathy and an abnormal shape of the brainstem has been described in patients harbouring de novo germline F1174V and F1245V ALK mutations. Here, we investigated the phenotype of knock-in (KI) mice bearing the AlkF1178L mutation (F1174L in human). Although heterozygous KI mice did not reproduce the severe breathing and feeding difficulties observed in human patients, behavioral tests documented a reduced activity during dark phases and an increased anxiety of mutated mice. Matings of heterozygotes yielded the expected proportions of wild-type, heterozygotes and homozygotes at birth but a high neonatal lethality was noticed for homozygotes. We documented Alk expression in several motor nuclei of the brainstem involved in the control of sucking and swallowing. Evaluation of basic physiological functions 12 hours after birth revealed slightly more apneas but a dramatic reduced milk intake for homozygotes compared to control littermates. Overall, our data demonstrate that Alk activation above a critical threshold is not compatible with survival in mice, in agreement with the extremely severe phenotype of patients carrying aggressive de novo ALK germline mutations.
[Show abstract][Hide abstract] ABSTRACT: Activating mutations of the ALK (Anaplastic lymphoma Kinase) gene have been identified in sporadic and familial cases of neuroblastoma, a cancer of early childhood arising from the sympathetic nervous system (SNS). To decipher ALK function in neuroblastoma predisposition and oncogenesis, we have characterized knock-in (KI) mice bearing the two most frequent mutations observed in neuroblastoma patients. A dramatic enlargement of sympathetic ganglia is observed in AlkF1178L mice from embryonic to adult stages associated with an increased proliferation of sympathetic neuroblasts from E14.5 to birth. In a MYCN transgenic context, the F1178L mutation displays a higher oncogenic potential than the R1279Q mutation as evident from a shorter latency of tumor onset. We show that tumors expressing the R1279Q mutation are sensitive to ALK inhibition upon crizotinib treatment. Furthermore, our data provide evidence that activated ALK triggers RET upregulation in mouse sympathetic ganglia at birth as well as in murine and human neuroblastoma. Using vandetanib, we show that RET inhibition strongly impairs tumor growth in vivo in both MYCN/KI AlkR1279Q and MYCN/KI AlkF1178L mice. Altogether, our findings demonstrate the critical role of activated ALK in SNS development and pathogenesis and identify RET as a therapeutic target in ALK mutated neuroblastoma.
[Show abstract][Hide abstract] ABSTRACT: Smoothened (SMO) inhibitors recently entered clinical trials for sonic-hedgehog-driven medulloblastoma (SHH-MB). Clinical response is highly variable. To understand the mechanism(s) of primary resistance and identify pathways cooperating with aberrant SHH signaling, we sequenced and profiled a large cohort of SHH-MBs (n = 133). SHH pathway mutations involved PTCH1 (across all age groups), SUFU (infants, including germline), and SMO (adults). Children >3 years old harbored an excess of downstream MYCN and GLI2 amplifications and frequent TP53 mutations, often in the germline, all of which were rare in infants and adults. Functional assays in different SHH-MB xenograft models demonstrated that SHH-MBs harboring a PTCH1 mutation were responsive to SMO inhibition, whereas tumors harboring an SUFU mutation or MYCN amplification were primarily resistant.
Cancer cell 03/2014; 25(3):393-405. · 25.29 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Medulloblastoma comprises four distinct molecular subgroups: WNT, SHH, Group 3, and Group 4. Current medulloblastoma protocols stratify patients based on clinical features: patient age, metastatic stage, extent of resection, and histologic variant. Stark prognostic and genetic differences among the four subgroups suggest that subgroup-specific molecular biomarkers could improve patient prognostication.
Molecular biomarkers were identified from a discovery set of 673 medulloblastomas from 43 cities around the world. Combined risk stratification models were designed based on clinical and cytogenetic biomarkers identified by multivariable Cox proportional hazards analyses. Identified biomarkers were tested using fluorescent in situ hybridization (FISH) on a nonoverlapping medulloblastoma tissue microarray (n = 453), with subsequent validation of the risk stratification models.
Subgroup information improves the predictive accuracy of a multivariable survival model compared with clinical biomarkers alone. Most previously published cytogenetic biomarkers are only prognostic within a single medulloblastoma subgroup. Profiling six FISH biomarkers (GLI2, MYC, chromosome 11 [chr11], chr14, 17p, and 17q) on formalin-fixed paraffin-embedded tissues, we can reliably and reproducibly identify very low-risk and very high-risk patients within SHH, Group 3, and Group 4 medulloblastomas.
Combining subgroup and cytogenetic biomarkers with established clinical biomarkers substantially improves patient prognostication, even in the context of heterogeneous clinical therapies. The prognostic significance of most molecular biomarkers is restricted to a specific subgroup. We have identified a small panel of cytogenetic biomarkers that reliably identifies very high-risk and very low-risk groups of patients, making it an excellent tool for selecting patients for therapy intensification and therapy de-escalation in future clinical trials.
Journal of Clinical Oncology 02/2014; · 17.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: DNA copy number profiles characterize regions of chromosome gains, losses, and breakpoints in tumor genomes. Although many models have been proposed to detect these alterations, it is not clear which model is appropriate before visual inspection the signal, noise, and models for a particular profile.
We propose SegAnnDB, a web-based computer vision system for genomic segmentation: first visually inspect the profiles and manually annotate altered regions, then SegAnnDB determines the precise alteration locations using a mathemetical model of the data and annotations. SegAnnDB facilitates collaboration between biologists and bioinformaticians, and uses the UCSC genome browser to visualize copy number alterations alongside known genes.
The breakpoints project on INRIA GForge hosts the source code, an Amazon Machine Image can be launched, and a demonstration web site is http://bioviz.rocq.inria.fr.
[Show abstract][Hide abstract] ABSTRACT: Purpose
Diagnosis of alveolar rhabdomyosarcoma (aRMS) is typically histological and immunohistochemical. Since 1993, we know that this tumor harbors specific fusion transcripts called PAX3-FOXO1 and PAX7-FOXO1. Detection by RT-PCR of one of these transcripts in bone marrow or circulating blood can reveal infra-cytological metastasis. The objective of this study was to determine the frequency of detection of bone marrow (BMM) and/or blood micrometastasis (CMM) in children with aRMS at diagnosis and to assess its prognostic value.
This is a French national clinico-biological retrospective study of 34 children and adolescents with rhabdomyosarcoma (RMS), metastatic or localized, of which the initial tumor harbors at least one specific transcript. They all had, at diagnosis, a bone marrow and/or blood sample to search micrometastasis.
Sixteen percent of patients with localized disease had BMM and 53 % of all aRMS had a CMM. Results indicate that the presence of BMM at diagnosis is associated with a significant decrease in overall survival (10 % vs 60 % ; P = 0.0058) and event-free survival (10 % vs 50 %; P = 0.0008), as well as in metastatic stage and localized tumors. We find, moreover, 83 % of relapse or progression in presence of blood micrometastasis.
With all the limitation of a retrospective analysis – and despite the limited number of patients – this is the first study to examine the pejorative prognostic value of the presence of bone marrow or blood micrometastasis at diagnosis in children with aRMS. It is the first step leading to a large-scale on going prospective study to confirm this assumption. If this is confirm in a larger setting, this would classify patients with bone marrow or blood micrometastasis in a high-risk population, to be treated more intensively or with new therapeutic strategies.
[Show abstract][Hide abstract] ABSTRACT: The present study describes a new case of EWSR1-negative undifferentiated sarcoma with CIC/DUX4 gene fusion. This case is similar to tumors described as primitive undifferentiated round cell sarcomas that occur mainly in the trunk and display an aggressive behavior. To our knowledge, this is the first report of such a tumor presenting locoregional lymph node metastasis. In view of previous studies that prove the existence of a particular variant of undifferentiated sarcoma with Ewing-like morphology and CIC/DUX-4 gene fusion, a search for this gene fusion in all undifferentiated round cell sarcomas should be considered if a conclusive diagnosis cannot be reached following other conventional studies. Although additional cases with more extensive follow-up studies are needed, we believe that EWSR1-negative undifferentiated small round cell sarcoma with CIC/DUX4 gene fusion should be added to the list of new sarcoma variants with the possibility of lymph node metastasis.
Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 11/2013; · 2.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: RNA interference has boosted the field of functional genomics, by making it possible to carry out "loss of function" screens in cultured cells. Here, we performed a siRNA screening, in three breast cancer cell lines, for 101 candidate driver genes overexpressed in amplified breast tumors and belonging to eight amplicons on chromosomes 8q and 17q, investigating their role in cell survival/proliferation. This screening identified eight driver genes that were amplified, overexpressed and critical for breast tumor cell proliferation or survival. They included the well described oncogenic driver genes for the 17q12 amplicon, ERBB2 and GRB7. Four of six other candidate driver genes - RAD21 and EIF3H, both on chromosome 8q23, CHRAC1 on chromosome 8q24.3 and TANC2 on chromosome 17q23 -were confirmed to be driver genes regulating the proliferation/survival of clonogenic breast cancer cells presenting an amplification of the corresponding region. Indeed, knockdown of the expression of these genes decreased cell viability, through both cell cycle arrest and apoptosis induction, and inhibited the formation of colonies in anchorage-independent conditions, in soft agar. Strategies for inhibiting the expression of these genes or the function of the proteins they encode are therefore of potential value for the treatment of breast cancers presenting amplifications of the corresponding genomic region.