Multivariate Analysis of RNA Chemistry Marks Uncovers Epitranscriptomics-Based Biomarker Signature for Adult Diffuse Glioma Diagnostics.

One of the main challenges in cancer management relates to the discovery of reliable biomarkers, which could guide decision-making and predict treatment outcome. In particular, the rise and democratization of high-throughput molecular profiling technologies bolstered the discovery of "biomarker signatures" that could maximize the prediction performance. Such an approach was largely employed from diverse OMICs data (i.e., genomics, transcriptomics, proteomics, metabolomics) but not from epitranscriptomics, which encompasses more than 100 biochemical modifications driving the post-transcriptional fate of RNA: stability, splicing, storage, and translation. We and others have studied chemical marks in isolation and associated them with cancer evolution, adaptation, as well as the response to conventional therapy. In this study, we have designed a unique pipeline combining multiplex analysis of the epitranscriptomic landscape by high-performance liquid chromatography coupled to tandem mass spectrometry with statistical multivariate analysis and machine learning approaches in order to identify biomarker signatures that could guide precision medicine and improve disease diagnosis. We applied this approach to analyze a cohort of adult diffuse glioma patients and demonstrate the existence of an "epitranscriptomics-based signature" that permits glioma grades to be discriminated and predicted with unmet accuracy. This study demonstrates that epitranscriptomics (co)evolves along cancer progression and opens new prospects in the field of omics molecular profiling and personalized medicine.

MET immunolabelling is a useful predictive tool for MET gene amplification in glioblastoma.

AIMS: MET gene amplification is rare in glioblastoma (GBM) and represents a potential target for MET inhibitors. An immunohistochemical screening may be useful to identify MET amplification. The aim of our study was to establish how MET immunolabelling correlates with MET amplification. METHODS: Three cohorts including 108 GBM (cohort 1, prospective), 104 GBM (cohort 2, retrospective) and 52 GBM (cohort 3, prospective) were investigated for MET expression by immunohistochemistry. MET amplification was assessed by comparative genomic hybridization on microarray (CGH-array) in all cohorts and by fluorescent in situ hybridization (FISH) in cohorts 2 and 3. Active form of MET was assessed using p-MET (Y1349) immunohistochemistry. RESULTS: Diffuse MET amplification detectable by CGH-array was associated with diffuse, strong MET immunolabelling (four cases in cohort 1 and one case in cohort 2). Focal MET amplification detectable only by FISH was observed in small foci of strongly immunopositive cells in two GBM (cohort 2). In both cohorts, MET amplification was never detected in GBM devoid of strongly immunopositive cells. MET overexpression, observed in 23% of unamplified GBM, was associated with a predominant weak-to-moderate staining intensity and with necrosis (P < 0.005). p-MET was detected in all MET-amplified GBM and in perinecrotic areas of nonamplified GBM. A strong MET immunostaining intensity, at least focal and distant from necrosis, showed 100% sensitivity and 84% specificity for predicting MET amplification in cohort 3. CONCLUSIONS: MET amplification is characterized by strongly immunopositive cells. Only GBM showing strong MET immunostaining is appropriate for the assessment of MET amplification.

Meningeal SWI/SNF related, matrix-associated, actin-dependent regulator of chromatin, subfamily B member 1 (SMARCB1)-deficient tumours: an emerging group of meningeal tumours.

AIMS: Bi-allelic inactivation of SWI/SNF related, matrix-associated, actin-dependent regulator of chromatin, subfamily B member 1 (SMARCB1; also known as INI1) and loss of immunohistochemical expression of SMARCB1 define the group of SMARCB1-deficient tumours. Initially highlighted in malignant rhabdoid tumours, this inactivation has subsequently been observed in several intra and extracranial tumours. To date, primary meningeal SMARCB1-deficient tumours have not been described. We report two cases of meningeal SMARCB1-deficient tumours occurring in adults. METHODS: We performed immunohistochemical analyses, comparative genomic hybridization, fluorescence in situ hybridization and targeted next-generation sequencing. RESULTS: The first meningeal tumour was a solitary mass, composed of rhabdoid, adenoid, chordoid and sarcomatoid areas. The second case presented as multiple, bilateral, supra and infratentorial nodules, was composed of fusiform and ovoid cells embedded in a myxoid stroma. Tumour cells were positive for epithelial membrane antigen (EMA), vimentin and CD34 and negative for SMARCB1 and meningothelial, melanocytic, muscular, glial markers. In the first case, one allele of SMARCB1 was completely deleted, whereas in the second case, loss of expression of SMARCB1 was observed as a consequence of a homozygous deletion of SMARCB1. CONCLUSIONS: The phenotype and genotype of these two cases did not fit diagnostically with entities already known to be SMARCB1-deficient tumours. As both tumours shared common features, they are regarded as belonging to an emerging group of primary meningeal SMARCB1-deficient tumours, not described to date. To facilitate the identification and characterization of these tumours, we recommend SMARCB1 immunohistochemistry for primary meningeal tumours which are difficult to classify, especially if immunopositive for EMA and CD34.

[Pulmonary intravascular talcosis: A case report]. / Talcose intravasculaire pulmonaire : à propos d'un cas.

INTRODUCTION: Pulmonary intravascular talcosis is a rare condition occurring in intravenous drug users injecting oral medications. Talc results in a foreign-body granulomatous reaction giving a radiological haematogenic miliary appearance mimicking miliary tuberculosis. Drug users represent a population at risk for both these conditions and their distinction may be challenging. CASE REPORT: We reported the case of a man, 33 year-old, intravenous drug addict, detected by the health services because he was the partner of a person who died of contagious and multi-resistant tuberculosis. Chest X-ray and CT scan showed a typical miliary appearance. Despite negative microbiology, clinical diagnosis of miliary tuberculosis was retained. Due to the lack of radiological improvement despite appropriate antibiotic treatment, re-evaluation and trans-bronchial biopsy were undertaken. The presence of granulomas centered by birefringent foreign bodies in polarized light led to a diagnosis of pulmonary intravascular talcosis. CONCLUSION: In the presence of pulmonary miliary in an intravenous drug addict, intravascular talcosis should be suspected.

DOCK4 promotes loss of proliferation in glioblastoma progenitor cells through nuclear beta-catenin accumulation and subsequent miR-302-367 cluster expression.

Glioblastomas (GBM) are lethal primitive brain tumours characterized by a strong intra-tumour heterogeneity. We observed in GBM tissues the coexistence of functionally divergent micro-territories either enriched in more differentiated and non-mitotic cells or in mitotic undifferentiated OLIG2 positive cells while sharing similar genomic abnormalities. Understanding the formation of such functionally divergent micro-territories in glioblastomas (GBM) is essential to comprehend GBM biogenesis, plasticity and to develop therapies. Here we report an unexpected anti-proliferative role of beta-catenin in non-mitotic differentiated GBM cells. By cell type specific stimulation of miR-302, which directly represses cyclin D1 and stemness features, beta-catenin is capable to change its known proliferative function. Nuclear beta-catenin accumulation in non-mitotic cells is due to a feed forward mechanism between DOCK4 and beta-catenin, allowed by increased GSK3-beta activity. DOCK4 over expression suppresses selfrenewal and tumorigenicity of GBM stem-like cells. Accordingly in the frame of GBM median of survival, increased level of DOCK4 predicts improved patient survival.

[Acute airway obstruction during chemotherapy-induced agranulocytosis with fever]. / Moules bronchiques au cours d'une agranulocytose fébrile post-chimiothérapie.

Acute airway obstruction caused by mucoid impaction can cause sometimes life-threatening respiratory distress. Bronchial plugging is usually observed in subjects with chronic diseases such as asthma, allergic bronchopulmonary aspergillosis, or cystic fibrosis. In children, it can be related to heart failure. Acute airway obstruction in a patient without a chronic respiratory disease is exceptional. We report the case of a patient who developed bronchial plugs obstructing the bronchi during a period of agranulocytosis induced by chemotherapy. The patient experienced acute respiratory distress with asphyxia. The plugs were composed of fibrin and required several fibroscopic procedures for clearance. To our knowledge, this is the first case report of acute airway obstruction by plugging during a period of agranulocytosis.

[Histological and molecular analysis of brain metastases]. / Analyse histologique et moléculaire des métastases cérébrales.

The first step in the diagnosis of a metastatic brain lesion is to exclude a primary central nervous sytem tumour, followed by verification or identification of the primary tumor site, in order to guide the clinician to specific therapy. In addition to morphological features, ancillary immunohistochemical study is most effective for the evaluation of a metastatic neoplasm of unknown primary. Although the main principles are same, there are slight variations in the approach to the secondary lesion in the central nervous system versus other regions. Indeed, immunohistochemical approach focuses on the most common tumor types associated with secondary brain colonization: lung cancer, breast cancer and melanoma. Several studies have reported that targeted therapies are capable of reducing brain metastases in melanoma or non-small cell lung cancer, sometimes with a high dramatic response. These results have clearly impacted routine neuropathological practice. It is likely that molecular subtyping of central nervous system metastases will play an increasing role in the future. In accordance with the recommendations of Inca (French national cancer institute), the pathologist develops appropriate strategies for molecular and immunohistochemical analysis, in order to provide results as soon as possible. This article summarizes the diagnosic approach to brain metastases, with a focus on the recent emergence of targeted therapies.

[Bilateral pulmonary nodules in an HIV-infected patient]. / Nodules pulmonaires bilatéraux chez un patient infecté par le VIH.

INTRODUCTION: Although infectious causes are the most common source of pulmonary nodules in HIV-infected patients, malignant diseases such as Kaposi sarcoma and lymphoma must also be considered. OBSERVATION: A 40 year-old man, diagnosed with HIV infection 16 years earlier and with a satisfactory viro-immunological control, was hospitalized for bilateral pulmonary nodules and a dorsal lytic mass. Bone and pleural biopsies showed a malignant epithelioid hemangioendothelioma. COMMENT: Epithelioid hemangioendothelioma is an uncommon low grade vascular tumor. We report the first case in an HIV-infected patient. Bilateral pulmonary nodules are common in this malignant disease but are not specific. In a HIV-infected patient, such clinical presentation is associated with numerous differential diagnoses and must be interpreted in relation to the immune status. CONCLUSION: In HIV-patients without immunosuppression, pulmonary nodules are often malignant. With the increased survival of these patients, these etiologies closer to those of non-infected patients.

Fibronectin expression in glioblastomas promotes cell cohesion, collective invasion of basement membrane in vitro and orthotopic tumor growth in mice.

Glioblastoma multiforme (GBM) are highly invasive and angiogenic malignancies with a median survival time from diagnosis of <15 months. Previous work has revealed robust overexpression of fibronectin (FN) mRNA in GBM, although immunohistochemical staining of FN in these tumors is typically associated with the angiogenic vasculature. Here we sought to examine the expression of tumor cell FN and address its possible involvement in the invasive phenotype of GBM. We found that FN was expressed and assembled into fibrillar arrays in human tumors and in established GBM lines. Cultured cells spontaneously formed dense cellular networks and spheroid-like domes. Depletion of FN by targeted-short hairpin RNA expression disrupted matrix assembly and multicellular network organization by exerting profound effects on cell adhesion and motility. Although FN depletion enhanced persistent directional migration of single cells, it compromised collective invasion of spheroids through a laminin-rich matrix and sensitized cells to ionizing radiation. In orthotopic grafts, FN depletion significantly reduced tumor growth and angiogenesis. Together our results show that FN produced by the tumor cells has a role in GBM pathophysiology and they provide insights into the implications that targeting FN interactions may have for combating this dreaded disease.

[Diagnosis of IgG4-related systemic disease in a patient with an ocular tumor associated with lung nodules]. / Diagnostic de syndrome d'hyper-IgG4 chez une patiente présentant une tumeur oculaire associée à des nodules pulmonaires.

The IgG4-related systemic disease is a recently described entity of fibro-inflammatory systemic damage. Although initially described in some forms of pancreatitis, the disease can affect all organs. The common histological features include a lymphoplasmacytic infiltration (especially to IgG4), fibrosis and phlebitis. Elevated serum level of IgG4 is also often present. This rare but certainly underdiagnosed disease must be kept in mind of all clinician faced to a non-specific inflammatory lesion. We report a case of ocular inflammation and lung tumors in a patient of 84 years for which the diagnosis was made through immunolabelling with IgG4 in lesions biopsied.