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Summary Activation of mitogenic signaling pathways is a common oncogenic driver of many solid tumors including lung cancer. Although activating mutations in the mitogen-activated protein kinase (MAPK) pathway are prevalent in non-small cell lung cancers, MAPK pathway activity, counterintuitively, is relatively suppressed in the more aggressively proliferative small cell lung cancer (SCLC). Here, we elucidate the role of the MAPK pathway and how it interacts with other signaling pathways in SCLC. We find that the most common SCLC subtype, SCLC-A associated with high expression of ASCL1, is selectively sensitive to MAPK activation in vitro and in vivo through induction of cell-cycle arrest and senescence. We show strong upregulation of ERK negative feedback regulators and STAT signaling upon MAPK activation in SCLC-A lines. These findings provide insight into the complexity of signaling networks in SCLC and suggest subtype-specific mitogenic vulnerabilities., Graphical abstract, Highlights • MAPK activation causes cell-cycle arrest and senescence selectively in SCLC-A subtype • MAPK-induced growth inhibition is independent of NOTCH signaling • MAPK activation increases ERK negative feedback and activates STAT3 signaling, Biological sciences; Cell biology; Molecular biology

Small cell lung cancer (SCLC) has limited therapeutic options and an exceptionally poor prognosis. Understanding the oncogenic drivers of SCLC may help define novel therapeutic targets. Recurrent genomic rearrangements have been identified in SCLC, most notably an in-frame gene fusion between RLF and MYCL found in up to 7% of the predominant ASCL1-expressing subtype. To explore the role of this fusion in oncogenesis and tumor progression, we used CRISPR/Cas9 somatic editing to generate a Rlf–Mycl-driven mouse model of SCLC. RLF–MYCL fusion accelerated transformation and proliferation of murine SCLC and increased metastatic dissemination and the diversity of metastatic sites. Tumors from the RLF–MYCL genetically engineered mouse model displayed gene expression similarities with human RLF–MYCL SCLC. Together, our studies support RLF–MYCL as the first demonstrated fusion oncogenic driver in SCLC and provide a new preclinical mouse model for the study of this subtype of SCLC. Significance: The biological and therapeutic implications of gene fusions in SCLC, an aggressive metastatic lung cancer, are unknown. Our study investigates the functional significance of the in-frame RLF–MYCL gene fusion by developing a Rlf–Mycl-driven genetically engineered mouse model and defining the impact on tumor growth and metastasis. This article is highlighted in the In This Issue feature, p. 2945

Extramedullary hematopoiesis (EMH) refers to the proliferationof hematopoietic precursors outside the bone marrow. EMH oftenpresents as a mass lesion in several areas of the body. In thisreport, we present a case misdiagnosed and explain the cause ofthe diagnostic error.

Background/aim: The purpose of this study was to evaluate the concordance of immunohistochemical (IHC) parameters of breast lesions between the core needle biopsy (CNB) and the surgical resection specimen. Materials and methods: CNB and resection specimens of female patients were retrospectively analyzed. ER, PR, HER-2, and Ki-67 parameters were compared for each patient. A total of 284 cases were assessed. Forty-one and 48 cases were excluded from the HER-2 and Ki-67 examinations, respectively, because the CNBs did not allow for IHC. Results: Concordance rates were 93.3% for ER, 89.4% for PR, 90.1% for HER-2, and 80.9% for Ki-67.Conclusion: CNB is accurate for the evaluation of the surrogate molecular profile of invasive breast cancer despite the heterogeneity of tumors.

Clear cell sarcoma-like tumor of the gastrointestinal tract (CCSLGT) is a rare and relatively recently described entity. Here, we report a CCSLGT arising in the ileum of 28-year-old man. Histologically, the tumor composed of uniform, epithelioid or spindle cells that have eosinophilic cytoplasm and round, vesicular nucleus with single prominent nucleolus arranged in nests. No melanin pigment is identified. Lymph nodes and liver revealed metastasis. Immunohistochemically, tumor cells labeled with S100, SOX10, while negative for Cam 5.2, HMB-45, A103, CD117, DOG-1, SMA, desmin, chromogranin and synaptophysin. Fluorescence in situ hybridization (FISH) analysis identified rearrangement of EWSR1 (22q12) gene and targeted next generation sequencing revealed characteristic EWSR1 - ATF1 fusion. The patient received systemic chemotherapy and is alive after eight months. CCSLGT should be kept in mind for any tumor arising from the wall of the gastrointestinal tract with epitheloid or spindle cell population that shows S100 expression and lack of melanocytic differentiation.

New therapeutic strategies are needed in the treatment of asthma besides vaccines and pharmacotherapies. For the development of novel therapies, the use of mesenchymal stem cells (MSCs) is a promising approach in regenerative medicine. Delivery of compact bone (CB) derived MSCs to the injured lungs is an alternative treatment strategy for chronic asthma. In this study, we aimed to isolate highly enriched population of MSCs from mouse CB with regenerative capacity, and to investigate the impact of these cells in airway remodeling and inflammation in experimental ovalbumin-induced mouse model of chronic asthma. mCB-MSCs were isolated, characterized, labeled with GFP and then transferred into mice with chronic asthma developed by ovalbumin (OVA) provocation. Histopathological changes including basement membrane, epithelium, subepithelial smooth thickness and goblet cell hyperplasia, and MSCs migration to lung tissues were evaluated. These histopathological alterations were increased in ovalbumin-treated mice compared to PBS group (P < 0.001). Intravenous administration of mCB-MSC significantly reduced these histopathological changes in both distal and proximal airways (P < 0.001). We showed that GFP-labeled MSCs were located in the lungs of OVA group 2 weeks after intravenous induction. mCB-MSCs also significantly promoted Treg response in ovalbumin-treated mice (OVA + MSC group) (P < 0.037). Our studies revealed that mCB-MSCs migrated to lung tissue and suppressed histopathological changes in murine model of asthma. The results reported here provided evidence that mCB-MSCs may be an alternative strategy for the treatment of remodeling and inflammation associated with chronic asthma. (C) 2014 Elsevier B.V. All rights reserved.

Bayramoglu Z, Yilmaz R, Demir AA, Ataizi-Celikel C, Kombak FE, Ikinci A, Yekeler E. Multimodality imaging findings of visceral myopathy in a child presenting with palpable abdominal mass. Turk J Pediatr 2019; 61: 120-125. Visceral myopathy is a rare cause of intestinal obstruction characterized by intestinal dysmotility and constipation. Patients often present with recurrent abdominal pain, vomiting and abdominal distension. We report a rare case of visceral myopathy in a child presenting with intraabdominal mass. We aimed to describe ultrasound, computed tomography and magnetic resonance enterography findings of this rare disease that has not been demonstrated before. Differential diagnosis of mural thickening with distinguishable layers in addition to intestinal dilatation in the absence of mesenteric inflammation includes visceral myopathy.

Angiomyxoma is a soft tissue tumor characterized by the presence of prominent myxoid matrix and numerous thin-walled blood vessels. It is usually located in trunk, head, neck, extremities and genitalia. Total excision of the tumor is the treatment method. Local recurrence is possible but metastases are not seen. We herein report the clinical, radiological and pathological findings of a rare case of angiomyxoma which is placed in the left breast parenchyma of a 3 years old female. The tumor developed rapidly in last six months and it had been seen like a grown up breast tissue.

New strategies are needed to suppress airway inflammation and prevent or reverse airway remodeling in asthma. Reprogramming induced pluripotent stem cells (iPSCs) have the potential of embryonic stem cells (ESCs) and provide a resource for stem cell-based utility. The aim of this study was to evaluate the histopathological and immunomodulatory effects of ESCs and iPSCs for potential allogenic application in a murine model of acute asthma. BALB/c mice were sensitized with alum-absorbed ovalbumin (OVA) and then challenged with 1% aerosolized OVA. 5 x 10(5) ESCs and iPSCs were administrated intranasally on the last day of nebulization. Mice were sacrificed after 24 h, and serum allergen specific antibody level, airway remodeling, cytokine levels in lung supernatants, and eosinophilic infiltration in BAL fluid were examined. As a result, more ESCs and iPSCs integrated into the lungs of mice in OVA groups than those of the controls. Epithelial, smooth muscle and basal membrane thicknesses as well as goblet cell hyperplasia occurring in airway remodeling were significantly suppressed by pluripotent stem cells in both distal and proximal airways. Percentage of eosinophils decreased significantly in BAL fluid as well as serum allergen-specific IgE and IL-4 levels in lung supernatants. On the contrary, regulatory cytokine - IL-10 level - was enhanced. Application of especially ESCs significantly increased the percentage of Treg subsets. Our comparative results showed that i.n. delivery of miRNA-based reprogrammed iPSCs is beneficial in attenuating airway inflammation in a murine model of acute asthma, and that cells also have similar immunomodulatory effects in mice. (C) 2014 Elsevier B.V. All rights reserved.