Wild-type VHL Clear Cell Renal Cell Carcinomas Are a Distinct Clinical and Histologic Entity: A 10-Year Follow-up

International audienceBackground: Clear cell renal cell carcinoma (ccRCC) is an aggressive tumor with 50% risk of metastases at initial diagnosis or at follow-up. An inactivation of the tumor-suppressor gene von Hippel-Lindau (VHL) is present in >70% of sporadic cases by two of three different mechanisms: locus deletion, gene mutation, or promoter hypermethylation. Objective: To correlate the complete status of the VHL gene with clinical and pathologic criteria. Design, setting, and participants We retrospectively included 98 patients with ccRCC who underwent surgery between 2002 and 2005. VHL gene deletions (71 of 98; 72.4%), mutations (68 of 98; 69.4%), and promoter hypermethylations (13 of 98; 13.3%) were screened by gene copy analysis, gene sequencing, and methylation-specific multiplex ligation-dependent probe amplification, respectively. Outcome measurements and statistical analysis Relationships between VHL subgroups and the studied criteria were analyzed using chi-square and Student t tests. Survival was analyzed with the log-rank test and Kaplan-Meier curves. Results and limitations: Compared with ccRCCs with two events (66.3%), tumors with no or one genetic event (33.6%) were associated with a higher nuclear grade IV (p = 0.02), metastases (p = 0.04), sarcomatoid component (p = 0.01), dense lymphocyte infiltrate (p = 0.013), and vascular endothelial growth factor overexpression (>30%) (p = 0.003), which was also an independent factor after multivariate analysis. Furthermore, wild-type VHL tumors (no inactivating event, 11.2%) were associated with nodal involvement (p = 0.019), and patients with this type of tumor had a specific survival of 33 mo compared with patients with ccRCCs having one or two VHL inactivating events (107 mo; p = 0.016). The retrospective design with small number of wild-type tumors was a limitation of this work. Conclusions: This long-term study (10-yr clinical follow-up) confirms that ccRCCs with wild-type VHL are highly aggressive tumors that need to be formally identified. Patient summary Among activated VHL tumors, the wild-type subgroup defines an aggressive phenotype with worse survival rates, suggesting that these tumors must be more thoroughly screene

Réversion tumorale : étude fonctionnelle de TSAP6 et TCTP.

During my PhD I studied two genes, TSAP6 and TCTP that are differentially regulated in tumor reversion. The proteins encoded by these two genes interact and form a complex both in vitro and in vivo. My goal was to better understand the biological function of these two genes. Different approaches were used, namely crystallography (TCTP), knockout mice (TSAP6 and TCTP) and site-directed mutagenesis (TSAP6 and TCTP). The TSAP6 knockout mice display a microcytic anemia. We have shown that this anemia is due to a delay in the maturation of the reticulocytes and a default in the secretion of the Transferrin-Receptor by the exosomes. Since TSAP6 is a direct transcriptional target gene of p53, we analyzed the secretion of exosomes following activation of p53 by irradiation or Actinomicine D. We demonstrate that in the absence of TSAP6, there is no induction in the secretion of exosomes. More generally, we show that the TSAP6 gene has a major role in vivo in the secretion of exosomes, including following activation of p53. We studied the TCTP gene in its antiapoptotic role. The deletion of TCTP in knockout mice is lethal. This loss of TCTP causes an increase of apoptosis during embryogenesis. This embryonic lethality occurs between days 6,5 and 9,5 of the development. The crystal structure of TCTP at 2A resolution shows a strong homology with the one of s.pombe protein. Furthermore, we observed a homology between the H2-H3 helices of TCTP and the H5-H6 helices of BAX, a proapoptotic protein involved in mitochondrial membrane permeability. We demonstrated that these two helices are responsible for the antiapoptotic function of TCTP, which inhibits the dimerization of BAX in the mitochondrial membrane, preventing this way cell death.We also show that Sertraline and Thioridazine, that kill tumor cells by decreasing the level of intracellular TCTP, bind directly to TCTP and prevent the formation of a complex between TSAP6 and TCTP.Mon travail de doctorat a consisté en l'étude de deux gènes, TSAP6 et TCTP, qui sont régulés de manière différentielle dans la réversion tumorale. Les protéines encodées par ces deux gènes interagissent et forment un complexe tant in vitro que in vivo. Mon objectif était de mieux comprendre la fonction biologique de ces deux gènes. Différentes approches ont été employées, notamment la cristallographie (TCTP), souris knockout (TSAP6 et TCTP) et études par mutagénèse dirigée (TSAP6 et TCTP). Les souris knockout pour le gène tsap6 présentent une anémie microcytaire. Nous démontrons que cette anémie est due à un retard de maturation des réticulocytes ainsi qu'à une sécrétion défectueuse du récepteur à la Transferrine par les exosomes. Étant donné que le gène TSAP6 est une cible transcriptionnelle directe de la p53, nous avons voulu analyser la sécrétion des exosomes suite à une stimulation de p53 (par rayon X ou Actinomicine D). Nous montrons qu'en l'absence de TSAP6, on ne parvient pas à stimuler une sécrétion des exosomes. De manière plus générale ces expériences ont démontré que le gène TSAP6 avait in vivo un rôle prédominant dans la sécrétion des exosomes, y compris suite à l'activation de la p53. Nous avons surtout étudié le rôle que joue TCTP dans l'apoptose. La délétion du gène tctp dans les souris knockout est létale en provoquant une augmentation de l'apoptose au cours de l'embryogenèse. Cette mort embryonnaire se produit entre les 6,5ème et 9,5ème jours du développement. La détermination de la structure de la protéine TCTP par cristallographie avec une résolution de 2A montre que la protéine humaine est très homologue à celle de s.pombe. De plus, nous avons observé suite à une analyse informatique une homologie de structure entre les hélices H2 et H3 de TCTP et les hélices H5 et H6 de BAX, une protéine pro-apoptotique impliquée dans la perméabilité de la membrane mitochondriale. On a démontré que grâce à ces deux hélices, TCTP effectue son action anti-apoptotique et inhibe la dimérisation de BAX à la membrane des mitochondries, empêchant ainsi l'apoptose.Nous montrons également que la Sertraline et la Thioridazine, qui induisent la mort des cellules tumorales et une baisse concomitante de TCTP, se lient directement à TCTP et empêchent ainsi la formation du complexe TSAP6-TCTP

Reversion tumorale (étude fonctionnelle de TSAP6 et TCTP)

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Biomarqueurs prédictifs de réponse aux inhibiteurs de points de contrôle immuns

National audienc

EFGR-mutant lung adenocarcinoma and Li-Fraumeni syndrome: Report of two cases and review of the literature.

International audienceWe report two cases of non-smoker patients diagnosed with EGFR-mutated lung adenocarcinoma and bearing germinal TP53 gene mutation, also known as Li-Fraumeni syndrome (LFS). We describe for the first time an EGFR-TKI resistance mutation in this population. Finally, we provide an analysis of discerning epidemiological data obtained from the IARC database and from all the published cases of EGFR-mutated lung cancer in TP53 germline mutation carriers

Genomic organization and expression of mouse Tpt1 gene☆

International audienceThe translationally controlled tumor protein (TCTP), also known as histamine-releasing factor (HRF), is encoded by a gene (Tpt1) that is highly conserved throughout phylogeny. TCTP is implicated in cell growth, acute allergic response, and apoptosis. In the present study, seven putative Tpt1 genes with different chromosomal localizations were identified in the mouse genome. In six of them, analysis of the 5' and 3' untranslated regions revealed the presence of flanking direct repeats and residual poly(A) tails typical of pseudogenes. Only three of the seven genes can produce a protein of the expected molecular weight. We isolated the genomic DNA of these three genes to analyze their sequence, genomic organization, and in vitro promoter activity. We found that mouse Tpt1 is localized on chromosome 14 with a canonical intron-exon organization, a functional promoter, and only one transcript that is ubiquitously expressed in all tissues

C-kit, B-raf, and N-ras mutations in melanoma subtypes

48th Annual Meeting of the American-Society-of-Clinical-Oncology (ASCO), Chicago, IL, JUN 01-06, 2012International audienceno abstrac

Depicting the genetic architecture of pediatric cancers through an integrative gene network approach

International audienceThe genetic etiology of childhood cancers still remains largely unknown. It is therefore essential to develop novel strategies to unravel the spectrum of pediatric cancer genes. Statistical network modeling techniques have emerged as powerful methodologies for enabling the inference of gene-disease relationship and have been performed on adult but not pediatric cancers. We performed a deep multi-layer understanding of pan-cancer transcriptome data selected from the Treehouse Childhood Cancer Initiative through a co-expression network analysis. We identified six modules strongly associated with pediatric tumor histotypes that were functionally linked to developmental processes. Topological analyses highlighted that pediatric cancer predisposition genes and potential therapeutic targets were central regulators of cancer-histotype specific modules. A module was related to multiple pediatric malignancies with functions involved in DNA repair and cell cycle regulation. This canonical oncogenic module gathered most of the childhood cancer predisposition genes and clinically actionable genes. In pediatric acute leukemias, the driver genes were co-expressed in a module related to epigenetic and post-transcriptional processes, suggesting a critical role of these pathways in the progression of hematologic malignancies. This integrative pan-cancer study provides a thorough characterization of pediatric tumor-associated modules and paves the way for investigating novel candidate genes involved in childhood tumorigenesis