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Purpose: Our objective was to identify the genetic changes involved in primary central nervous system lymphoma (PCNSL) oncogenesis and evaluate their clinical relevance.Experimental Design: We investigated a series of 29 newly diagnosed, HIV-negative, PCNSL patients using high-resolution single-nucleotide polymorphism (SNP) arrays (n = 29) and whole-exome sequencing (n = 4) approaches. Recurrent homozygous deletions and somatic gene mutations found were validated by quantitative real-time PCR and Sanger sequencing, respectively. Molecular results were correlated with prognosis.Results: All PCNSLs were diffuse large B-cell lymphomas, and the patients received chemotherapy without radiotherapy as initial treatment. The SNP analysis revealed recurrent large and focal chromosome imbalances that target candidate genes in PCNSL oncogenesis. The most frequent genomic abnormalities were (i) 6p21.32 loss (HLA locus), (ii) 6q loss, (iii) CDKN2A homozygous deletions, (iv) 12q12-q22, and (v) chromosome 7q21 and 7q31 gains. Homozygous deletions of PRMD1, TOX, and DOCK5 and the amplification of HDAC9 were also detected. Sequencing of matched tumor and blood DNA samples identified novel somatic mutations in MYD88 and TBL1XR1 in 38% and 14% of the cases, respectively. The correlation of genetic abnormalities with clinical outcomes using multivariate analysis showed that 6q22 loss (P = 0.006 and P = 0.01) and CDKN2A homozygous deletion (P = 0.02 and P = 0.01) were significantly associated with shorter progression-free survival and overall survival.Conclusions: Our study provides new insights into the molecular tumorigenesis of PCNSL and identifies novel genetic alterations in this disease, especially MYD88 and TBL1XR1 mutations activating the NF-κB signaling pathway, which may be promising targets for future therapeutic strategies. Clin Cancer Res; 18(19); 5203–11. ©2012 AACR.

PDF file, 55K, Table S1: Recurrent chromosome region imbalances found in more than 20% of PCNSLs investigated by high resolution genomic arrays.

Early detection of breast cancer through mammography is crucial for successful treatment. Microcalcifications are small deposits of calcium in breast ducts, they can be an indication of breast cancer and are first detected by mammography. However, their presence must be confirmed by an histopathologist through slides examination. As a help to practitioners, we present an automatic microcalcification detection pipeline in Whole Slide Images (WSI). This pipeline is a patch-based approach, in which patches from epithelial regions are analyzed by a classifier to determine if they contain microcalcifications. We have developed two classifiers for this pipeline, one based on image processing techniques and the other on deep learning. In addition to standard classification metrics, we compare the performance of these two classifiers using custom metrics specifically designed to capture the value brought by the pipeline to pathologists. Both approaches provide promising results. The deep learning classifier has better metrics, but requires more labeled data to be implemented.

Background The EndoPredict (EP) test has been developed and validated for assessing recurrence risk in patients with estrogen receptor (ER)-positive HER2-negative breast cancer (BC). This test is based on the expression of 12 genes (molecular score), combined with clinicopathological criteria (i.e. tumor size and nodal status) (EPclin risk score). For node-positive patients, the weight given to the node status in the EPclin score is similar when considering pN1mi (]0.2-2mm]) or pN1 (>2mm, 1-3 positive lymph nodes). Our aim was to characterize the EPclin classification of the pN1mi subgroup in the French national registry for molecular signatures in ER+ BC. Methods Since April 2016, nine French laboratories using EP test in clinical practice prospectively implement a national registry for molecular prognostic signatures in ER+ BC. We analyzed the pN1mi subgroup with regards to their clinico-pathological characteristics, molecular EP score and EPclin risk score. Using the definition formula of the EPclin score [EPclin=0.35t + 0.64n + 0.28EP, with n=1 for pN0, 2 for pN1mi/pN1, 3 for pN2, 4 for pN3], we could calculate a hypothetical EPclin score if the pN1mi had been considered as pN0 [n factor=1]. Results By the end of 2017, the database included 1246 EP tests performed in routine practice, including 67 (5.4%) pN1mi. The pN1mi BC were ER+ HER2- (67/67, 100%), invasive carcinoma of no special type in 52/67 (78%), with a median tumor size of 18 mm (range 7-45; pT1c in 40/67). Among these, 22 were classified as EPclin low and 45 as EPclin high, with a median EP score of 6 (range 2-14), a median EPclin score of 3.70 (range 3-6), and a median relapse risk at 10-year of 15%(range 5-73). Most interestingly, 23/67 (34%; i.e. 1.8% of all EP tests performed) pN1mi BC displayed an EPclin score comprised between 3.4 and 4, just above the cut-off value of 3.3: these cases (and only these cases) would have been classified in a different risk category (i.e. EPclin low risk) if the node status would have been considered as negative. Conclusion With regards to EndoPredict test in pN1mi BC - and the persistent debate as to whether they should bear the same weight as node-positive (pN1) or negative (pN0) tumors - categorization in the EPclin class is not likely to be impacted by the node factor weight in the vast majority (>65%) of the pN1mi cases and >98% of all patients tested with EP. Only cases with an EPclin between 3.4 and 4 might be impacted. Citation Format: LaCroix-Triki M, Arnould L, MacGrogan G, Penault-Llorca F, Haudebourg J, Tas P, Garnier A, Vincent-Salomon A, Miquel C, Lehmann-Che J, Callens C, Quillien V, Cayre A, Lamy P-J, Rouleau E, De Cremoux P. EndoPredict prognostic signature in pN1mi, estrogen receptor-positive breast cancer: analysis of the French national registry for molecular signatures [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-23.

Background: Patients with triple-negative breast cancers (TNBC) have a poor prognosis unless a pathological complete response (pCR) is achieved after neoadjuvant chemotherapy (NAC). Few studies have analyzed changes in TIL levels following dose-dense dose-intense (dd-di) NAC. Patients and methods: From 2009 to 2018, 117 patients with TNBC received dd-di NAC at our institution. We aimed to identify factors associated with pre- and post-NAC TIL levels, and oncological outcomes relapse-free survival (RFS), and overall survival (OS). Results: Median pre-NAC and post-NAC TIL levels were 15% and 3%, respectively. Change in TIL levels with treatment was significantly correlated with metabolic response (SUV) and pCR. High post-NAC TIL levels were associated with a weak metabolic response after two cycles of NAC, with the presence of residual disease and nodal involvement at NAC completion. In multivariate analyses, high post-NAC TIL levels independently predicted poor RFS and poor OS (HR = 1.4 per 10% increment, 95%CI (1.1; 1.9) p = 0.014 and HR = 1.8 per 10% increment 95%CI (1.3–2.3), p < 0.0001, respectively). Conclusion: Our results suggest that TNBC patients with TIL enrichment after NAC are at higher risk of relapse. These patients are potential candidates for adjuvant treatment, such as immunotherapy, in clinical trials.

Inflammatory breast cancers are very aggressive, and among them, triple negative breast cancer (TNBC) has the worst prognosis. While many studies have investigated the association between tumor-infiltrating lymphocytes (TIL) before neoadjuvant chemotherapy (NAC) and outcome in TNBC, the impact of post-NAC TIL and TIL variation in triple negative inflammatory breast cancer (TNIBC) outcome is unknown. Between January 2010 to December 2018, all patients with TNIBC seen at the breast disease unit (Saint-Louis Hospital) were treated with dose-dense dose-intense NAC. The main objective of the study was to determine factors associated with event-free survival (EFS), particularly pathological complete response (pCR), pre- and post-NAC TIL, delta TIL and post-NAC lymphovascular invasion (LVI). After univariate analysis, post-NAC LVI (HR 2.06, CI 1.13&ndash, 3.74, p = 0.02), high post-NAC TIL (HR 1.81, CI 1.07&ndash, 3.06, p = 0.03) and positive delta TIL (HR 2.20, CI 1.36&ndash, 3.52, p = 0.001) were significantly associated with impaired EFS. After multivariate analysis, only a positive TIL variation remained negatively associated with EFS (HR 1.88, CI 1.05&ndash, 3.35, p = 0.01). TNIBC patients treated with intensive NAC who present TIL enrichment after NAC have a high risk of relapse, which could be used as a prognostic marker in TNIBC and could help to choose adjuvant post-NAC treatment.

International audience; An intraductal carcinoma, 55 mm across, was diagnosed on a total mastectomy in a 45-year-old woman. The 2 micro-invasive areas found were too small for reliable immunostainings for estrogen, progesterone, and HER2 receptors. In the sentinel lymph-node, a subcapsular tumor embole of about 50 cancer cells was identified on the extemporaneous cryo-cut section, but not on further sections after paraffinembedding of the sample. Considering this tumor metastatic potential, we decided to assess HER2 status on the metastatic embole using pathological and molecular micro-methods. We lasermicrodissected the tumor cells, extracted their DNA, and performed droplet-digital-PCR (ddPCR) for HER2 gene copy number variation. The HER2/RNaseP allele ratio was 5.2 in the laser-microdissected tumor cells, similar to the 5.3 ratio in the HER2overexpressing breast cancer cell line BT-474. We thus optimized the adjuvant treatment of our patient and she received a trastuzumab-based adjuvant chemotherapy.

The basal transcription/repair factor TFIIH is a ten sub-unit complex essential for RNA polymerase II (RNAP2) transcription initiation and DNA repair. In both these processes TFIIH acts as a DNA helix opener (by the enzymatic activity of the XPB and XPD helicases), required for promoter escape of RNAP2 in transcription initiation, and to set the stage for strand incision within the Nucleotide Excision Repair (NER) pathway. We generated a knock-in mouse model that endogenously expresses a fluorescent version of XPB. Here we demonstrate, via confocal imaging of ex vivo tissues and cells derived from this mouse model, that TFIIH steady state levels are tightly regulated at the single cell level, thus keeping nuclear TFIIH concentrations remarkably constant in a cell type dependent manner. Moreover, we show that individual cellular TFIIH levels are proportional to the speed of mRNA production, hence to a cell’s transcriptional activity, which we can correlate to proliferation status. Importantly, cancer tissue presents a higher TFIIH than normal healthy tissues. Taken together, these results show that TFIIH cellular concentration might be used as a bona-fide marker of transcriptional activity and proliferation.SignificanceUsing a mouse model expressing a fluorescently version of TFIIH, we showed that TFIIH concentration is tightly controlled and that this concentration is proportional to the cellular transcriptional activity and proliferation capacity.

Cancer cells often express differentiation programs unrelated to their tissue of origin, although the contribution of these aberrant phenotypes to malignancy is poorly understood. An aggressive subgroup of medulloblastoma, a malignant pediatric brain tumor of the cerebellum, expresses a photoreceptor differentiation program normally expressed in the retina. We establish that two photoreceptor-specific transcription factors, NRL and CRX, are master regulators of this program and are required for tumor maintenance in this subgroup. Beyond photoreceptor lineage genes, we identify BCL-XL as a key transcriptional target of NRL and provide evidence substantiating anti-BCL therapy as a rational treatment opportunity for select MB patients. Our results highlight the utility of studying aberrant differentiation programs in cancer and their potential as selective therapeutic vulnerabilities.

OBJECTIVEThe goal of this study was to provide insight into the influence of gliomas on gestational outcomes, the impact of pregnancy on gliomas, and the identification of patients at risk.METHODSIn this multiinstitutional retrospective study, the authors identified 52 pregnancies in 50 women diagnosed with a glioma.RESULTSFor gliomas known prior to pregnancy (n = 24), we found the following: 1) An increase in the quantified imaging growth rates occurred during pregnancy in 87% of cases. 2) Clinical deterioration occurred in 38% of cases, with seizures alone resolving after delivery in 57.2% of cases. 3) Oncological treatments were immediately performed after delivery in 25% of cases. For gliomas diagnosed during pregnancy (n = 28), we demonstrated the following: 1) The tumor was discovered during the second and third trimesters in 29% and 54% of cases, respectively, with seizures being the presenting symptom in 68% of cases. 2) The quantified imaging growth rates did not significantly decrease after delivery and before oncological treatment. 3) Clinical deterioration resolved after delivery in 21.4% of cases. 4) Oncological treatments were immediately performed after delivery in 70% of cases. Gliomas with a high grade of malignancy, negative immunoexpression of alpha-internexin, or positive immunoexpression for p53 were more likely to be associated with tumor progression during pregnancy. Deliveries were all uneventful (cesarean section in 54.5% of cases and vaginal delivery in 45.5%), and the infants were developmentally normal.CONCLUSIONSWhen a woman harboring a glioma envisions a pregnancy, or when a glioma is discovered in a pregnant patient, the authors suggest informing her and her partner that pregnancy may impact the evolution of the glioma clinically and radiologically. They strongly advise a multidisciplinary approach to management.■ CLASSIFICATION OF EVIDENCE Type of question: association; study design: case series; evidence: Class IV.

The 2016 WHO classification of tumours of the central nervous system represents the new paradigm among the specialists in the brain tumours and proposes a new approach combining histopathological and molecular features into diagnosis named 'integrated diagnosis'. The aim of this challenge is to overstep the interobserver variability of diagnosis based on previous classifications in order to ensure homogenous biological entities with a more accurate clinical significance. Over the last two decades, several molecular aberrations into gliomagenesis were highlighted and then confirmed as emerging biomarkers through prognostic stratification. In particular, IDH1/IDH2 genes mutations, 1p/19q codeletion and mutations in genes encoding histone H3 variants drastically changed the knowledge about diffuse gliomas inducing the WHO working group to consider the phenotype-genotype approach. In the present review, the historical development of the diagnosis of brain tumours from the 3D spatial configuration to the integration of multidisciplinary data up to recent molecular alterations is discussed. At the national level, the RENOCLIP network (supported by the National Cancer Institute) contributes to improve the standardization of histological diagnosis and the facilitation of access to molecular biology platforms for the detection of genetic aberrations necessary for integrated diagnosis. Importantly, the French POLA cohort allowed to test the clinical impact of the new criteria introduced by 2016 WHO classification of CNS tumours confirming the high accuracy in predicting clinical behaviour for diffuse gliomas.

Objective The DEPDC5 (DEP domain-containing protein 5) gene, encoding a repressor of the mTORC1 signaling pathway, has recently emerged as a major gene mutated in familial focal epilepsies. We aimed to further extend the role of DEPDC5 to focal cortical dysplasias (FCDs). Methods Seven patients from 4 families with DEPDC5 mutations and focal epilepsy associated with FCD were recruited and investigated at the clinical, neuroimaging, and histopathological levels. The DEPDC5 gene was sequenced from genomic blood and brain DNA. Results All patients had drug-resistant focal epilepsy, 5 of them underwent surgery, and 1 had a brain biopsy. Electroclinical phenotypes were compatible with FCD II, although magnetic resonance imaging (MRI) was typical in only 4 cases. Histopathology confirmed FCD IIa in 2 patients (including 1 MRI-negative case) and showed FCD I in 2 other patients, and remained inconclusive in the last 2 patients. Three patients were seizure-free postsurgically, and 1 had a worthwhile improvement. Sequencing of blood DNA revealed truncating DEPDC5 mutations in all 4 families; 1 mutation was found to be mosaic in an asymptomatic father. A brain somatic DEPDC5 mutation was identified in 1 patient in addition to the germline mutation. Interpretation Germline, germline mosaic, and brain somatic DEPDC5 mutations may cause epilepsy associated with FCD, reinforcing the link between mTORC1 pathway and FCDs. Similarly to other mTORopathies, a “2-hit” mutational model could be responsible for cortical lesions. Our study also indicates that epilepsy surgery is a valuable alternative in the treatment of drug-resistant DEPDC5-positive focal epilepsies, even if the MRI is unremarkable.

Resume L’efficacite du traitement chirurgical des epilepsies partielles pharmaco-resistantes (EPPR) sur le controle des crises et la qualite de vie est aujourd’hui bien etablie. La selection des candidats repose sur les donnees cliniques, electrophysiologiques et sur l’imagerie. Celle-ci permet d’identifier les principales etiologies des EPPR curables par la chirurgie : la sclerose hippocampique, responsable de la majorite des epilepsies mesio-temporales, les tumeurs de bas grade d’origine developpementale – DNTs et gangliogliomes – les dysplasies corticales focales, les lesions vasculaires et cicatricielles. Un bilan prechirurgical comprenant video-EEG, imagerie anatomique et fonctionnelle, evaluation neuropsychologique et psychiatrique, effectue dans un centre de reference, confirme l’indication et evalue les risques de la chirurgie. Dans certains cas, une implantation d’electrodes intracerebrales pour enregistrement EEG invasif (SEEG) est necessaire pour identifier la localisation et l’etendue de la region cerebrale responsable des crises et definir la strategie chirurgicale. Les techniques chirurgicales se sont diversifiees et comprennent les interventions de resection–temporale, extra-temporale, en region fonctionnelle –, les interventions de destruction focale, de deconnexion et de neuromodulation. La prise en charge postoperatoire est pluridisciplinaire et comprend la gestion du traitement antiepileptique, le traitement des comorbidites, l’aide a la reinsertion. Les resultats de la chirurgie sur les crises d’epilepsie dependent avant tout de l’etiologie : la suppression des crises est observee chez 60 % a 80 % des patients dans l’epilepsie mesio-temporale, chez plus de 80 % des patients apres resection tumorale et dans plus de 90 % des patients operes d’une dysplasie corticale focale. La guerison des crises est suivie d’une amelioration significative de la qualite de vie. Le declin de la memoire apres intervention sur le lobe temporal peut etre predit sur des donnees cliniques et d’imagerie fonctionnelle. D’autres defis demeurent a relever, dont la reduction des delais d’acces a la chirurgie, l’amelioration des resultats dans l’epilepsie mesio-temporale et l’identification pre- et intra-operatoire des lesions epileptogenes non visibles sur l’imagerie.

Medulloblastoma (MB) is the most common malignant brain tumor of childhood arising in the cerebellum. Although multimodal treatments have significantly increased the survival, 20–30% of patients remain incurable. Most of them belong to a poorly characterized MB subgroup, called group3, which expresses a retina photoreceptor-specific differentiation program. Cancer cells often express such differentiation programs unrelated to their tissue of origin. They likely result from cancer cell plasticity but are usually not thought to contribute to cancer progression. Accordingly, the functional relevance of this aberrant differentiation program to MB remains unknown. By analyzing group3 enhancers (Enh) and super-enhancers (SE), we identified key interconnected transcription factors of this subgroup, Among those, two lineage restricted transcription factors, NRL and CRX, are known to play key roles during retina development and in particular for photoreceptor specification. We identified a list of genes harboring a co-occurrence of NRL and CRX binding sites within Enh/SE, and displaying higher expression in group3. Interestingly, photoreceptors genes are enriched among this list. This analysis showed that NRL and CRX are important players in group3 MB and control the photoreceptor differentiation program. By loss-of-function experiments in cell lines and PDXs, we showed that NRL and CRX are absolutely required for MB growth in vitro and in vivo upon orthotopic grafting. We then confirmed that NRL controls the expression of photoreceptor genes in group3 MB and established that it protects MB from apoptosis. By ChIP experiments we identified one of its key target genes in this process: the anti-apoptotic BCL-XL gene. We confirmed its key role downstream of NRL by rescue experiments. Importantly, we established the potential of anti-BCL therapies in MB. In conclusion, we showed that the photoreceptor program is instrumental to MB through NRL and CRX and that the anti-BCL therapies could represent an alternative therapeutic strategy.

The aim of this study was to review and describe therapeutic approaches in children with choroid plexus tumor (CPT) based on a nationwide series. The World Health Organization classification subdivides these rare tumors into three histological subtypes corresponding to three grades of malignancy: low grade (grade I) choroid plexus papilloma (CPP), intermediate grade (grade II) atypical choroid plexus papilloma (aCPP) and high grade (grade III) choroid plexus carcinoma (CPC). This retrospective study included 102 French children younger than 18 years, treated from 2000 to 2012: 54 CPP, 26 aCPP and 22 CPC. The 5 year overall survival was 100% in CPP, 96.2% in aCPP and 64.7% in CPC. In patients with localized disease, complete surgical resection was achieved in 48/52 CPP, 20/26 aCPP and 7/14 CPC. In this group, patients with complete surgical resection had better event free survival than patients with partial resection (88.9 vs. 41.6%). 28 patients (1 CPP, 6 aCPP and 22 CPC) had adjuvant chemotherapy. 2 aCPP and 9 CPC had radiotherapy. We underlined the need for a central histological review to accurately analyze clinical data; we reported a much higher overall survival for CPC than in most previous CPT series probably including atypical teratoid rhabdoid tumors. In our series, the 5 years overall survival in CPC (64.7%) was higher than event free survival (25.2%) and could be interpreted as a clue for the efficiency of adjuvant/salvage therapy even if the heterogeneity of applied treatments in this retrospective series does not allow for meaningful statistical comparisons.

Background Brain metastases challenge daily clinical practice, and the mechanisms by which cancer cells cross the blood-brain barrier remain largely undeciphered. Angiopoietin-like 4 (ANGPTL4) proteolytic fragments have controversial biological effects on endothelium permeability. Here, we studied the link between ANGPTL4 and the risk of brain metastasis in cancer patients. Methods From June 2014 to June 2015, serum samples from 86 cancer patients were prospectively collected, and ANGPTL4 concentrations were assessed. Using a murine model of brain metastases, we investigated the roles of nANGPTL4 and cANGPTL4 fragments in the occurrence of brain metastases. Results A positive ANGPTL4 serum concentration over 0.1ng/mL was associated with decreased overall-survival. Multivariate analyses found that only breast cancer brain metastases were significantly associated with elevated ANGPTL4 serum concentrations. 4T1 murine breast cancer cells were transfected with either nANGPTL4- or cANGPTL4-encoding cDNAs. Compared to mice injected with wild-type 4T1 cells, mice injected with nANGPTL4 cells had shorter median survival (p Conclusions This study opens the way for further translational research on the role of cANGPTL4 fragment in human breast cancer brain metastases.

The aim of this study was to better define the clinical and biopathological features of patients with desmoplastic/nodular medulloblastoma (DNMB) and to further characterize this subgroup. 17 children aged < 5 years, with initial DNMB treated according to the HIT-SKK protocol, were evaluated. A retrospective central radiological review, a pathological and immunohistochemical study, and array-CGH and sequencing of germline SUFU and PTCH1 genes were performed. 15 histologically reviewed cases were confirmed as DNMB including three cases of medulloblastoma with extensive nodularity. Median age at diagnosis was 26 months. Radiology showed five cases with a vermis location and one with T2 hyperintensity. All cases showed a SHH immuno-profile. A 9q deletion was found in 6 cases, a MYCN–MYCL amplification in 1 case, and a SUFU germline mutation in 1 case (/9). The presence of SUFU and PTCH1 germline mutations agreed with previous reports. At 3 years, progression-free survival and overall-survival rates were 72 ± 15% and 85 ± 10%, respectively. The rate of recurrence was relatively high (4 patients). This may have been because chemotherapy was delayed in two cases. Age > 3 years, and residual tumor may also have been an explanation for recurrence.

Introduction Les hyperparathyroidies primaires (HPT1) sont generalement diagnostiquees par la survenue d’une hypercalcemie. Il existe cependant des formes normocalcemiques. Objectif Identifier les determinants biologiques des HPT1 normo- et hypercalcemiques et notamment l’influence potentielle du poids des glandes parathyroides (PTx) des patients. Patients/materiels et methodes A partir d’une cohorte de 1500 patients lithiasiques et hypercalciuriques explores pour un test de charge en calcium, 72 patients ayant une HPT1 ont ete etudies. Une comparaison entre les groupes normocalcemiques (n = 25) et hypercalcemiques (n = 47) a ete realisee. Le poids des PTx etait disponible respectivement chez 12 et 33 patients. Resultats Le poids des PTx est comparable entre les deux groupes (p = 0,94). Les patients hypercalcemiques ont une parathormone (PTH) comparable aux normocalcemiques avant charge, mais plus elevees apres charge calcique (p = 0,01). TRAP5b et calcium/creatinine urinaire a jeun, deux marqueurs de resorption osseuse, sont egalement plus eleves (p = 0,01 et p = 0,02). La fraction d’excretion urinaire du calcium (FE Ca) a jeun est plus elevee (p = 0,009), mais identique pour FE Ca post-charge. Les apports en calcium, la calciurie des 24 heures, l’absorption digestive du calcium (delta calcium/creatinine) les phosphates et le calcitriol plasmatiques sont comparables entre les deux groupes. Apres ajustement les seuls facteurs associes a une hypercalcemie sont une PTH apres charge et une FE Ca plus elevees (p = 0,03 et p = 0,01 respectivement). Discussion Le poids des PTx etant comparables, ces resultats suggerent une relative inhibition du CaSR au niveau des PTx et potentiellement egalement au niveau renal (FE Ca pre-charge dans le groupe hypercalcemique significativement inferieur a FE Ca post-charge dans le groupe normocalcemique pour des calcium ionises comparables). Conclusion Dans notre population, la presence d’une hypercalcemie n’est pas associee au poids des PTx mais pourrait etre expliquee par une relative inhibition du CaSR au niveau des PTx, des os et du tubule renal.

CERVOXY COLL; International audience

Primary central nervous system lymphoma (PCNSL) is a rare extranodal diffuse large B-cell lymphoma (DLBCL) restricted to the CNS and associated with a poor prognosis. Despite a notable effort contributing to better characterize the genomic basis of these tumors, few molecular abnormalities were proposed as predictive or prognostic biomarkers. Recently, two hotspot mutations, C228T and C250T, and the polymorphism rs2853669, located within TERT core promoter region have known a growing interest due to their prognostic value in a wide range of tumors, including melanoma, hepatocellular carcinoma or glioblastoma. Forty-one PCNSL tumor samples of newly diagnosed PCNSL were sequenced for C228T and C250T TERT somatic mutations. TERT promoter mutations status was correlated with clinical outcome and rs2853669 genotype. We identified C228T and C250T mutations and rs2853669 genotype in 20%, 9.4% and 50%, respectively. No case with co-occurrence of C228T and C250T mutations was identified. C228T mutations, but not C250T, were significantly associated with shorter overall survival (OS) (median OS = 4.5 months vs 33 months for non-mutated, p = 0.0048) and progression free survival (PFS) (median PFS = 3 months vs 11.5 months for non-mutated, p = 0.0260). We found no association between TERT promoter mutations and the rs2853669 genotype. To our knowledge, we showed the presence of TERT promoter mutations in PCNSL for the first time. In addition, C228T promoter mutation was associated with a poor outcome. Considering that these mutations are known to confer enhanced TERT promoter activity, we speculate that an increased telomerase activity could play a role in PCNSL aggressiveness. This work was granted by the LOC study group network (réseau national de centres experts des lymphomes primitifs du SNC, INCa), the Ligue contre le Cancer (Comité du Val d’Oise), the Fondation pour la Recherche Médicale (FDT20140930968), the APHP-CRIC 2013 (assistance publique - hôpitaux de Paris), and the Association pour la Recherche sur les Tumeurs Cérébrales. Citation Format: Aurélie Bruno, Mailys Daniau, Karima Mokhtari, Amithys Rahimian, Marc Polivka, Anne Jouvet, Clovis Adam, Dominique Figarella-Branger, Catherine Miquel, Sandrine Eimer, Caroline Houillier, Carole Soussain, Agusti Alentorn, Khê Hoang-Xuan. Recurrent TERT promoter mutations in primary central nervous system lymphoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3896. doi:10.1158/1538-7445.AM2015-3896

Background: Primary central nervous system lymphoma (PCNSL) is a rare extranodal diffuse large B-cell lymphoma (DLBCL). Little is known about the genomic basis of tumorigenesis in PCNSL partly explained by the rarity of biological material available for research studies. PCNSL patients display poor outcomes compared to systemic DLBCL and it is still unclear whether this is linked to the organ-specific microenvironment or reflects a specific, aggressive, intrinsic biological behavior. To our knowledge, the mutational landscape of PCNSL has never been investigated Experimental design: We analyzed 9 paired tumor and germline DNA samples from PCNSL patients by high throughput exome sequencing. Then, we performed focused sequencing in 28 additional PCNSL tumors to validate somatic genomic alterations and better estimate their incidence. Mutational data were correlated with copy number variations (CNV) identified by SNP and CGH arrays and clinical data. Results: We identified recurrent somatic mutations in genes involved in key signalling pathways such as NFκB (i.e. MYD88, CD79B, TBL1XR1), B cell differentiation (i.e. ETV6, EBF1, IRF4) and cell cycle control (i.e. BTG1, PIM1). We found somatic mutations on MYD88 (38%), CD79B (30%), TBL1XR1 (22%) or ETV6 (16%) genes and described bi-allelic inactivation of TBL1XR1 and ETV6 genes. Interestingly, the correlation with the outcome showed a significant negative impact of TBL1XR1 mutation on survival in a multivariate analysis. Conclusions: The present study showed that PCNSLs have high genetic heterogeneity and that their mutational patterns display similarities with extracerebral DLBCL, particularly of the ABC subtype, suggesting shared underlying biological mechanisms. These results provide new insights into the mutational landscape of PCNSL and potential targets for therapeutic strategies. This work benefited from the LOC study group network (réseau national de centres experts des lymphomes primitifs du SNC, INCa). Citation Format: Aurélie Bruno, Blandine Boisselier, Karim Labreche, Yannick Marie, Marc Polivka, Anne Jouvet, Clovis Adam, Dominique Figarella-Branger, Catherine Miquel, Anne Vital, Caroline Houillier, Carole Soussain, Karima Mokhtari, Romain Daveau, Khê Hoang-Xuan. Mutational analysis of primary central nervous system lymphoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5192. doi:10.1158/1538-7445.AM2014-5192