Molecular Anomalies Research Articles

UM171 Modified Cord Blood Achieves Excellent Survival and Disease Control after 2 Years of Follow-up in High and Very High Risk Malignancies

UM171 Modified Cord Blood Achieves Excellent Survival and Disease Control after 2 Years of Follow-up in High and Very High Risk Malignancies

Modalités de capture des anomalies cytogénétiques et moléculaires pour la leucémie aiguë, le myélome multiple, le syndrome myélodysplasique, le syndrome myéloprolifératif et le syndrome myélodysplasique/myéloprolifératif : recommandations de la Société francophone de greffe de moelle et de thérapie cellulaire (SFGM-TC)

In an effort to standardize hematopoietic stem cell allograft procedures, the Francophone bone marrow transplantation and Cell Therapy Society (SFGM-TC) organized the 9th Allograft Harmonization Practice Workshop in Lille in September 2018. The purpose of these workshops is to propose a consensual attitude to the centers that wish it. In this workshop, we discuss how to capture the cytogenetic and molecular abnormalities of acute leukaemias, myelomas, myelodysplasias, myeloproliferative syndromes and myelodysplastic/myeloproliferative syndromes in the database common to all European transplant centers called ProMISe and managed by the European Society for Blood and Marrow Transplantation (EBMT). The complexity of cytogenetic and molecular data makes it difficult to enter data into the ProMISe registry. This workshop proposes a tool for input assistance, in tabular form by pathology. The main recommendation for the karyotype remains that of the complex karyotype that must be entered in "Full caryotype". Concerning the molecular anomalies, it is necessary to enter all the items proposed by ProMISe. In reviewing all the sheets proposed by ProMise, we note the absence of some relevant elements that can be added later.

Squamous cell lung cancer: genomic evolution and personalized therapy.

To review the state-of-the-art in relation to the current information on squamous cell lung cancer (SCLC). We describe the genetic anomalies reported, their effect, and finally the most promising therapeutic agents. We reviewed published articles in peer-reviewed journals as well as current treatment guidelines from local and international resources. SCLC represents a smaller proportion of the global burden of disease for lung cancer compared to its more frequent presentation, the adenocarcinoma. However, more than 400 000 cases are reported annually, a substantial population for whom therapeutic options are scarce and with limited efficacy. Several groups have been given the task of elucidating the mechanisms that lead to the development of SCLC, including molecular anomalies that can be used as targets for drug design. There are potential therapeutic targets for SCLC, which must be studied in clinical trials for validation.

AcSé-ESMART: European Proof of Concept Therapeutic Stratification Trial of Molecular Anomalies in Relapsed or Refractory Tumors in Children and Adolescents–Arm D: Olaparib and irinotecan.

10047 Background: AcSé-ESMART is a proof-of-concept, phase I/II, multicenter, prospective basket trial designed to explore targeting agents in a molecularly enriched cancer population; treatment arms with targeted agents as single agent or in combination regimens are explored independently. Arm D explores the PARP inhibitor olaparib (ola) in combination with irinotecan (iri). The design is based on the hypothesis that in pediatric cancer pathogenic BRCA alterations are extremely rare and proliferative capacity is high requiring a chemotherapy sensitisation approach. Preclinical data in pediatric cancer suggest PARP inhibitor activity in other genomic alterations impairing homologous recombination (HR) and demonstrate synergy with iri. We here report the results of the Phase I part of the trial. Methods: Children and adolescents with relapsed/refractory cancer and comprehensive molecular profiling (whole exome and RNA sequencing) at relapse were eligible. Dose-escalation followed a continuous reassessment method design of pre-specified dose combinations of oral ola and iv iri. Plasma for pharmacokinetics (PK) was collected. Results: From Oct 2016 to April 2018, 27 pts (19 sarcomas, 3 brain tumors, 5 other) with a median age of 15 y (range 4;22) were enrolled over 4 dose levels. Dose limiting toxicities occurred in 7 of 24 evaluable pts (gastrointestinal (n = 4), febrile neutropenia (n = 1), thrombocytopenia (n = 2)). The RP2D was defined as ola 90 mg/m2 BID day 1-10 and iri 20 mg/m2 day 4-8. Twenty-three pts evaluable for response received a median of 2 cycles (range 1-27+). Confirmed PRs were seen in one osteosarcoma, one pinealoblastoma and one neuroblastoma; time to progression was 22.4, 50 and 89+ weeks, respectively. Eight pts experienced disease stabilization (median 14.8 weeks, range 9;42.3). PK and biomarker analysis (ie. HR alterations, DNA and gene expression signatures) is ongoing to identify factors associated with clinical benefit and data will be presented. Conclusions: The RP2D of the combination is ola 90 mg/m2 BID day 1-10 and iri 20 mg/m2 day 4-8. Preliminary activity led to the ongoing Phase II part of the arm. Clinical trial information: NCT02813135.

Gene Expression Profiling of Lung Atypical Carcinoids and Large Cell Neuroendocrine Carcinomas Identifies Three Transcriptomic Subtypes with Specific Genomic Alterations

IntroductionDNA mutational profiling showed that atypical carcinoids (ACs) share alterations with large cell neuroendocrine carcinomas (LCNECs). Transcriptomic studies suggested that LCNECs are composed of two subtypes, one of which shares molecular anomalies with SCLC. The missing piece of information is the transcriptomic relationship between ACs and LCNECs, as a direct comparison is lacking in the literature. MethodsTranscriptomic and genomic alterations were investigated by next-generation sequencing in a discovery set of 14 ACs and 14 LCNECs and validated on 21 ACs and 18 LCNECs by using custom gene panels and immunohistochemistry for Men1 and Rb1. ResultsA 58-gene signature distinguished three transcriptional clusters. Cluster 1 comprised 20 LCNECs and one AC harboring concurrent inactivation of tumor protein p53 gene (TP53) and retinoblastoma 1 gene (RB1) in the absence of menin 1 gene (MEN1) mutations; all cases lacked Rb1 nuclear immunostaining. Cluster 3 included 20 ACs and four LCNECs lacking RB1 alterations and having frequent MEN1 (37.5%) and TP53 mutations (16.7%); menin nuclear immunostaining was lost in 75% of cases. Cluster 2 included 14 ACs and eight LCNECs showing intermediate features: TP53, 40.9%; MEN1, 22.7%; and RB1, 18.2%. Patients in cluster C1 had a shorter cancer-specific survival than did patients in C2 or C3. ConclusionsACs and LCNECs comprise three different and clinically relevant molecular diseases, one AC-enriched group in which MEN1 inactivation plays a major role, one LCNEC-enriched group whose hallmark is RB1 inactivation, and one mixed group with intermediate molecular features. These data support a progression of malignancy that may be traced by using combined molecular and immunohistochemical analysis.

Multiparameter flow cytometry applications in the diagnosis of mixed phenotype acute leukemia.

Mixed phenotype acute leukemias (MPALs) represent a rare subgroup of acute leukemias with a poor prognosis. Proper diagnosis and classification of MPAL is extremely important for patients' outcome. Morphology and flow cytometry recognize two types of MPAL: the "bilineal" MPAL with the coexistence of two blast populations of different lineage and truly "biphenotypic" MPAL coexpressing markers of more than one lineage in a homogenous blast population, respectively. The WHO 2008 classification further delineated three categories: associated with t(9;22)/BCR-ABL1 fusion gene, associated with KMT2A (mixed lineage leukemia) rearrangements, and nonotherwise specified. These categories remained unchanged in the WHO2016 update. Molecular studies have further underlined the heterogeneity of MPAL. In this review, rules for the correct assignment of acute leukemia to the MPAL category are discussed, including both flow cytometry and immunohistochemistry on bone marrow or other tissues biopsies. Comparison of the immunophenotypic classification proposals is provided outlining the explorations mandatory for definitive diagnosis. An extensive review of published data summarizes the reported cytogenetic and molecular anomalies. New developments in the understanding of the early stages of hematopoiesis provide clues to the possible etiopathology of these diseases. Finally, current treatment recommendations are summarized and referenced for clinical use, pointing out that allogeneic hematopoietic stem cell transplantation at an early stage should be considered (at least in adult patients). © 2019 International Clinical Cytometry Society.

Neuroprotective Effects of N - Acetyl - Methoxytryptamine in a Neurotoxic Mice Model of Huntington’s Disease Induced by Quinolinic Acid

Huntington’s Disease (HD) is an autosomal dominant neuropathology associated with severe degeneration in neurons of the basal ganglia. It is characterized by progressive motors symptoms, cognitive deficits and dementia. The genetic mutation induces trinucl eotide repeat expansion (TNR) of cytosine, adenine and guanine (CAG). The CAG - repeat is translated into a poly glutamine (polyQ) stretch caused by molding of DNA “loop out” structures and DNA slippage during the replication. This expanded sequence encodes a mutant huntingtin (mHtt), which is associated to neuronal dysfunction, cellular death, ubiquitous molecular and cellular anomalies. Furthermore, there are progressive impairments in motor control, cognitive function and mood. Quinolinic acid (QA) is an e xcitotoxic compound in humans and animals that has been linked to HD. N - acetyl - methoxytryptamine (MLT) is a hormone that produce anti - oxidant and anti - inflammatory effects on cell damage. The principal aim of this study is to know if QA induces damage in s triatal astrocytes and neurons and to evidence how MLT can participate as a neuroprotectant agent against the neurotoxic injury. We inoculate QA intrastriatal in 8 weeks old wild type (WT) female mice as endogenous neurotoxic model of HD. Here, we worked w ith three different groups of mice, and the striatal injection was administrated in all animals. PBS were inoculated in control mice; the second group was injected only QA; and the last group was pre - treated with MLT 30 min before the QA injection. Immunob lots, oxidative stress biomarkers, histological assay of astrocytes and neurons were evaluated as well as rotarod and open field tests. There was a reduction in proteins levels of BDNF and NeuN in QA mice. Contrary effects in lysates showed NF - κB, IκB α , HT T, GFAP and NRs. The analysis of CAT, SOD, Gpx and GSH showed decreased activity, while MDA displayed increased activation in QA mice. The animals pre - treated with MLT revers the tendency of proteins and antioxidant biomarkers; the HTT perinuclear staining in neurons was reduced. NeuN histochemistry showed a greater number of NeuN + cells; the astrogliosis was attenuated; and locomotor activities improved. Analysis of RT - PCR do no show significant diferences between teatments. This study suggests that MLT c an induce a compensatory response to neurotoxic stress againts neuro - glial injury. Thus, increasing MLT levels may be a promising treatment for HD disorder.

From cellular morphology to molecular and epigenetic anomalies of myelodysplastic syndromes.

Myelodysplastic syndromes (MDSs) are a myeloid neoplasm with a propensity for natural evolution or transformation to acute leukemias (AL) over time. Mechanisms for MDS transformation to AL remain poorly understood but are related to genomic instability, which affects the production of the different cell lineages. Genomic instability is also generated by dysfunctional telomeres. Indeed telomeres, the protective ends of chromosomes are the backbone of genome stability. Nuclear telomere remodeling is an early indicator of nuclear remodeling preceding the onset of genomic instability and MDS. This review aims to revisit the pathogenesis and pathophysiology of MDS from morphology and cytogenetics to molecular and epigenetic mechanisms. Furthermore, this review will highlight and discuss recent breakthroughs in dysfunctional telomeres and nuclear telomere architecture roles in the pathogenesis and physiopathology of MDS in the global context of genomic instability.

Eye-Tracking Study to Enhance Usability of Molecular Diagnostics Reports in Cancer Precision Medicine.

We conducted usability studies on commercially available molecular diagnostic (MDX) test reports to identify strengths and weaknesses in content and form that drive clinical decision making. Given routine genomic testing in cancer medicine, oncologists must interpret MDX reports as well as evidence concerning clinical utility of biomarkers accurately for treatment or trial selection. This work aims to evaluate effectiveness of MDX reports in facilitating cancer treatment planning. Fourteen clinicians at an academic tertiary care medical facility, with a wide range of experience in oncology and in the use of molecular testing, participated in this study. Three commercially available, widely used, Clinical Laboratory Improvement Amendments (CLIA)-certified, College of American Pathologists (CAP)-accredited test reports (labeled Laboratories A, B, and C) were used. Eye tracking, surveys, and think-aloud protocols were used to collect usability data for these MDX reports focusing on ease of comprehension and actionability. Clinicians found two primary areas in molecular diagnostic reports most useful for patient care: therapy options with benefit or lack of benefit to patients, including enrolling clinical trials; and pathogenic tumor molecular anomalies detected. Therapeutic implications and therapy classes such as US Food and Drug Administration-approved off-label, on-label, clinical trials were critical for decision making. However, all reports had usability and comprehension issues in these areas and could be improved. Focused usability studies can help drive our understanding of the clinical workflow for use of molecular diagnostic tests in cancer care. This in turn can have major effects on quality of care, outcomes, costs, and patient satisfaction. This study demonstrates the use of specific usability techniques (eye tracking and think-aloud protocols) to help clinical laboratories improve MDX report design in a precision oncology treatment setting.

CBNPC avec translocation ALK/ROS

The discovery of ALK and ROS1 rearrangements paved the way for the targeting of these molecular anomalies in lung cancer patients. These molecular abnormalities are comparable in their activation mechanism, treatment, and treatment-resistance mechanisms. Their prognosis is significantly different, with ALK generally causing more aggressive tumors. We detail in this review the molecular, clinical and therapeutic characteristics of tumors carrying these rearrangements.

TAP: a targeted clinical genomics pipeline for detecting transcript variants using RNA-seq data

BackgroundRNA-seq is a powerful and cost-effective technology for molecular diagnostics of cancer and other diseases, and it can reach its full potential when coupled with validated clinical-grade informatics tools. Despite recent advances in long-read sequencing, transcriptome assembly of short reads remains a useful and cost-effective methodology for unveiling transcript-level rearrangements and novel isoforms. One of the major concerns for adopting the proven de novo assembly approach for RNA-seq data in clinical settings has been the analysis turnaround time. To address this concern, we have developed a targeted approach to expedite assembly and analysis of RNA-seq data.ResultsHere we present our Targeted Assembly Pipeline (TAP), which consists of four stages: 1) alignment-free gene-level classification of RNA-seq reads using BioBloomTools, 2) de novo assembly of individual targets using Trans-ABySS, 3) alignment of assembled contigs to the reference genome and transcriptome with GMAP and BWA and 4) structural and splicing variant detection using PAVFinder. We show that PAVFinder is a robust gene fusion detection tool when compared to established methods such as Tophat-Fusion and deFuse on simulated data of 448 events. Using the Leucegene acute myeloid leukemia (AML) RNA-seq data and a set of 580 COSMIC target genes, TAP identified a wide range of hallmark molecular anomalies including gene fusions, tandem duplications, insertions and deletions in agreement with published literature results. Moreover, also in this dataset, TAP captured AML-specific splicing variants such as skipped exons and novel splice sites reported in studies elsewhere. Running time of TAP on 100–150 million read pairs and a 580-gene set is one to 2 hours on a 48-core machine.ConclusionsWe demonstrated that TAP is a fast and robust RNA-seq variant detection pipeline that is potentially amenable to clinical applications. TAP is available at http://www.bcgsc.ca/platform/bioinfo/software/pavfinder

Sex differences in DEK expression in the anterior cingulate cortex and its association with dementia severity in schizophrenia

DEK is a chromatin-remodeling phosphoprotein found in most human tissues, but its expression and function in the human brain is largely unknown. DEK depletion in vitro induces cellular and molecular anomalies associated with cognitive impairment, including down-regulation of the canonical Wnt/β-catenin signaling pathway. ToppGene analyses link DEK loss to genes associated with various dementias and age-related cognitive decline. To examine the role of DEK in cognitive impairment in severe mental illness, DEK protein expression was assayed by immunoblot in the anterior cingulate cortex (ACC) of subjects with schizophrenia. Cognitive impairment is a core feature of schizophrenia and cognitive function in subjects was assessed antemortem using the clinical dementia rating (CDR) scale. DEK protein expression was not significantly altered in schizophrenia (n = 20) compared to control subjects (n = 20). Further analysis revealed significant reduction in DEK protein expression in women with schizophrenia, and a significant increase in expression in men with schizophrenia, relative to their same-sex controls. DEK protein expression levels were inversely correlated with dementia severity in women. Conversely, in men, DEK protein expression and dementia severity were positively correlated. Notably, there was no sex difference in DEK protein expression in the control group, suggesting that this sex difference is specific to schizophrenia and not due to inherent differences in DEK expression between males and females. These results suggest a novel, sex-specific role for DEK in cognitive performance and highlight a putative sex-specific link between central nervous system DEK protein expression and a neuropsychiatric disease that is commonly associated with cognitive impairment.

Multiple Ways to Detect IDH2 Mutations in Angioimmunoblastic T-Cell Lymphoma from Immunohistochemistry to Next-Generation Sequencing

Angioimmunoblastic T-cell lymphoma (AITL) is a peripheral T-cell lymphoma associated with chemoresistance and a poor prognosis. Various nonsynonymous mutations in the R172 residue of IDH2 are present in 20% to 30% of AITL patients. In addition to their diagnostic value, these mutations are potentially targetable, especially by isocitrate dehydrogenase (IDH) 2 inhibitor, and therefore their identification in a routine setting is clinically relevant. However, in AITL, the neoplastic cells may be scarce, making the identification of molecular anomalies difficult. We evaluated the diagnostic value of different methods to detect IDH2 mutations in formalin-fixed, paraffin-embedded tumor samples. Immunohistochemistry with an anti-IDH2 R172K antibody, Sanger sequencing, high-resolution melting PCR, allele-specific real-time quantitative PCR, and next-generation sequencing (NGS) were applied to biopsy specimens from 42 AITL patients. We demonstrate that the IDH2 R172K antibody is specific to this amino acid substitution and highly sensitive for the detection of the IDH2R172K variant, the most frequent substitution in this disease. In our study, NGS and allele-specific real-time quantitative PCR displayed a good sensitivity, detecting 96% and 92% of IDH2 mutations, respectively, in contrast to Sanger sequencing and high-resolution melting PCR, which showed a significantly lower detection rate (58% and 42%, respectively). These results suggest that a combination of immunohistochemistry and AS-PCR or NGS should be considered for the identification of IDH2 mutations in AITL in a routine setting.

Essais de phase précoce à l’Institut de cancérologie de l’Ouest : réponse au traitement et validation de scores pronostiques

Early phase therapeutic trials in oncology are being offered to an increasing number of patients. The objective of this study is to retrospectively evaluate the treatment efficacy and survival of patients included in early phase trials at the "Institut de Cancérologie de l'Ouest" (ICO), as well as the interest of the Royal Marsden Hospital (RMH) and PRONOPALL scores in this population. All patients with cancer screened or included for an early phase trial at ICO between January 2012 and December 2015 have been identified. Out of 1312-screened patients, 710 were included in 115 trials (34 phase 1 trials). The absence of molecular anomaly was the main cause of inclusion failure (49.5%). The disease control rate was 90.9%, the median overall survival was 14.7 months (95%CI 12.7 to 16.4) and the median progression-free survival was 5.7 months (95%CI 5.5 to 6.6). The median overall survival was better for patients with good prognosis based on Royal Marsden Hospital score (16.6 months versus 6 months, P=0.0011) and PRONOPALL score (15.6 months versus 4.6 months, P<0.001). Our results are better than in the literature, mainly because of the high proportion of first-line treatments and the consideration of phase II trials. Patients with lung cancer particularly benefited from these treatments, in part because of the role of immunotherapy. The Royal Marsden Hospital score can guide the decision to include in early phase trials, whereas the PRONOPALL score is not enough efficient.

Potassium Bromate-induced Changes in the Adult Mouse Cerebellum Are Ameliorated by Vanillin

ObjectiveThe current study aimed to elucidate the effect of vanillin on behavioral changes, oxidative stress, and histopathological changes induced by potassium bromate (KBrO3), an environmental pollutant, in the cerebellum of adult mice. MethodsThe animals were divided into four groups: group 1 served as a control, group 2 received KBrO3, group 3 received KBrO3 and vanillin, and group 4 received only vanillin. We then measured behavioral changes, oxidative stress, and molecular and histological changes in the cerebellum. ResultsWe observed significant behavioral changes in KBrO3-exposed mice. When investigating redox homeostasis in the cerebellum, we found that mice treated with KBrO3 had increased lipid peroxidation and protein oxidation in the cerebellum. These effects were accompanied by decreased Na+-K+ and Mg2+ ATPase activity and antioxidant enzyme gene expression when compared to the control group. Additionally, there was a significant increase in cytokine gene expression in KBrO3-treated mice. Microscopy revealed that KBrO3 intoxication resulted in numerous degenerative changes in the cerebellum that were substantially ameliorated by vanillin supplementation. Co-administration of vanillin blocked the biochemical and molecular anomalies induced by KBrO3. ConclusionOur results demonstrate that vanillin is a potential therapeutic agent for oxidative stress associated with neurodegenerative diseases.

MED13L-related intellectual disability: involvement of missense variants and delineation of the phenotype.

Molecular anomalies in MED13L, leading to haploinsufficiency, have been reported in patients with moderate to severe intellectual disability (ID) and distinct facial features, with or without congenital heart defects. Phenotype of the patients was referred to "MED13L haploinsufficiency syndrome." Missense variants in MED13L were already previously described to cause the MED13L-related syndrome, but only in a limited number of patients. Here we report 36 patients with MED13L molecular anomaly, recruited through an international collaboration between centers of expertise for developmental anomalies. All patients presented with intellectual disability and severe language impairment. Hypotonia, ataxia, and recognizable facial gestalt were frequent findings, but not congenital heart defects. We identified seven de novo missense variations, in addition to protein-truncating variants and intragenic deletions. Missense variants clustered in two mutation hot-spots, i.e., exons 15-17 and 25-31. We found that patients carrying missense mutations had more frequently epilepsy and showed a more severe phenotype. This study ascertains missense variations in MED13L as a cause for MED13L-related intellectual disability and improves the clinical delineation of the condition.

Identification of Two Novel Fibrinogen Bβ Chain Mutations in Two Slovak Families with Quantitative Fibrinogen Disorders.

Congenital fibrinogen disorders are caused by mutations in one of the three fibrinogen genes that affect the synthesis, assembly, intracellular processing, stability or secretion of fibrinogen. Functional studies of mutant Bβ-chains revealed the importance of individual residues as well as three-dimensional structures for fibrinogen assembly and secretion. This study describes two novel homozygous fibrinogen Bβ chain mutations in two Slovak families with afibrinogenemia and hypofibrinogenemia. Peripheral blood samples were collected from all subjects with the aim of identifying the causative mutation. Coagulation-related tests and rotational thromboelastometry were performed. All exons and exon–intron boundaries of the fibrinogen genes (FGA, FGB and FGG) were amplified by PCR followed by direct sequencing. Sequence analysis of the three fibrinogen genes allowed us to identify two novel homozygous mutations in the FGB gene. A novel Bβ chain truncation (BβGln180Stop) was detected in a 28-year-old afibrinogenemic man with bleeding episodes including repeated haemorrhaging into muscles, joints, and soft tissues, and mucocutaneous bleeding and a novel Bβ missense mutation (BβTyr368His) was found in a 62-year-old hypofibrinogenemic man with recurrent deep and superficial venous thromboses of the lower extremities. The novel missense mutation was confirmed by molecular modelling. Both studying the molecular anomalies and the modelling of fibrinogenic mutants help us to understand the extremely complex machinery of fibrinogen biosynthesis and finally better assess its correlation with the patient’s clinical course.

Inter-and Intra-Laboratory Standardization of TUNEL Assay for Assessment of Sperm DNA Fragmentation.

The functional aspects of sperm activity such as sperm chromatin integrity and ability to fertilize cannot be characterized by routine semen parameters. Men with unexplained infertility and idiopathic infertility, as well as men with normozoospermic semen profiles, show high DNA fragmentation. Molecular anomalies in the sperm can be detected by a sperm DNA fragmentation (SDF) assay which can be used in adjunct to conventional semen analysis. While the sperm chromatin structure assay (SCSA) remains the "gold standard," the TUNEL assay using flow cytometry is becoming popular among the different tests that are currently available to measure sperm DNA fragmentation. In this unit, we describe the inter-laboratory and intra-laboratory standardization of the TUNEL assay using a benchtop cytometer. The article also provides a step-by-step protocol for measuring sperm DNA fragmentation using the TUNEL assay and a bench-top flow cytometer, and also points out the inherent challenges with this test. © 2017 by John Wiley & Sons, Inc.

Hobnail Variant of Papillary Thyroid Carcinoma: a Literature Review.

Papillary thyroid carcinoma is the most common thyroid malignancy and it is usually associated with a good prognosis. However, recurrence, metastases, and cancer death may occur in 10 to 15% of patients with more aggressive types of papillary thyroid carcinoma, such as tall cell, columnar cell, solid variant, or the more recently described hobnail variant of papillary thyroid carcinoma. Papillary thyroid carcinoma with a prominent hobnail pattern is a moderately differentiated papillary thyroid carcinoma variant with aggressive clinical behavior and significant mortality. The hobnail variant of papillary thyroid carcinoma shows prominent hobnail features, which have also been referred to as micropapillary. The typical hobnail/micropapillary morphological features show loss of cellular polarity/cohesiveness and support an epithelial-mesenchymal transition as a possible mechanism of metastasis. BRAF p.V600E is the most common mutation in papillary thyroid carcinoma, including the hobnail variant; recent and continuing studies are focused on defining other molecular anomalies that may be useful for prognostic stratification and may provide therapeutic targets.

Abstract CT004: European pediatric precision medicine program in recurrent tumors: first results from MAPPYACTS molecular profiling trial towards AcSe-ESMART proof-of-concept study

Abstract In the area of precision medicine we initiated the multi-centric, international trials MAPPYACTS ‘A multicentric, prospective proof-of-concept study MoleculAr Profiling for Pediatric and Young Adult Cancer Treatment Stratification’ (NCT02613962) and AcSé-ESMART ‘European Proof-of-Concept Therapeutic Stratification Trial of Molecular Anomalies in Relapsed or Refractory Tumors’ (NCT02813135). Design: Patients with pediatric recurrent or refractory malignancy underwent on-purpose tumor biopsy or surgical resection for molecular characterization by whole exome and RNA sequencing. A molecular tumor board of scientists and clinician-scientists reviewed results to determine the biological significance of the alterations which were discussed with the treating physician in a clinical molecular tumor board. Patients were treated whenever possible in an adapted clinical trial or the hypothesis-driven ESMART proof-of concept trial for which comprehensive molecular profile at relapse was mandatory and an enrichment strategy was applied. Results: From February 2016 to January 2017, 174 patients with a median age of 13 years (range, 1-32) were included in MAPPYACTS in 11 French centers. 39% had sarcomas, 25% brain tumors, 24% other solid tumor, 12% hematological malignancies. Currently, 104 patients have been completely analyzed and discussed. Of these, screening failed for 8.6% of patients. 95 patients underwent intervention by biopsy (72%), surgical resection (24%) or blood/bone marrow sampling (4%). Sufficient material was achieved in 81% of patients, 76 had whole exome, 68 RNA, 1 panel gene sequencing. For 76% of patients, at least one target was found that was considered ‘actionable’ and a total of 123 genomic alterations were decisional for the treatment suggestion. Alterations were CNA (56/123), somatic mutation (41), CNA + somatic mutation (11), gene fusion (6), germline mutation (3) germline mutation + CNA (3), CNA + fusion (2), expression (1). Based on the detected alteration, 21 patients were included in the ESMART trial since it opened in August 2016, two of these patients were included in two different arms: with the CDK4/6 inhibitor ribociclib plus chemotherapy (1) or everolimus (5), DNA repair interfering combinations WEE1 inhibitor AZD1775 plus chemotherapy (4) and PARP inhibitor olaparib plus chemotherapy (1), dual mTOR inhibitor vistusertib alone (1) or with chemotherapy (5), or nivolumab and cyclophosphamide (6). 15 of the 23 inclusions were considered enriched as per detected alteration. 5 patients were included in other early clinical trials with a targeted agent. Updated results will be presented at the meeting. Conclusion: MAPPYACTS shows the feasibility in a multicentric setting and confirms that actionable molecular alterations are frequently found in recurrent pediatric cancers. However few tumors have unique targetable driver events and proof-of-concept trials are crucial to explore innovate combination strategies in an enriched setting. Citation Format: Birgit Geoerger, Gudrun Schleiermacher, Gaelle Pierron, Ludovic Lacroix, Marc Deloger, Nadia Bessoltane, Anne Catherine Harttrampf, Stefan Michiels, Jean Yves Scoazec, Paul Freneaux, Xavier Paoletti, Olivier Delattre, Natalie Hoog-Labouret, Gilles Vassal. European pediatric precision medicine program in recurrent tumors: first results from MAPPYACTS molecular profiling trial towards AcSe-ESMART proof-of-concept study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT004. doi:10.1158/1538-7445.AM2017-CT004