Silvia Calabuig-Fariñas

Facilitated Anion Transport Induces Hyperpolarization of the Cell Membrane That Triggers Differentiation and Cell Death in Cancer Stem Cells

Facilitated anion transport potentially represents a powerful tool to modulate various cellular functions. However, research into the biological effects of small molecule anionophores is still at an early stage. Here we have used two potent anionophore molecules inspired in the structure of marine metabolites tambjamines to gain insight into the effect induced by these compounds at the cellular level. We show how active anionophores, capable of facilitating the transmembrane transport of chloride and bicarbonate in model phospholipid liposomes, induce acidification of the cytosol and hyperpolarization of plasma cell membranes. We demonstrate how this combined effect can be used against cancer stem cells (CSCs). Hyperpolarization of cell membrane induces cell differentiation and loss of stemness of CSCs leading to effective elimination of this cancer cell subpopulation.

Clinicopathological significance of cell cycle regulation markers in a large series of genetically confirmed Ewing's Sarcoma Family of Tumors

More than 90% of all Ewings Sarcoma Family of Tumors (ESFT) exhibit specific chromosomal rearrangements between the EWS gene on chromosome 22 and various members of the ETS gene family of transcription factors. The gene fusion type and other secondary genetic alterations, mainly involving cell cycle regulators, have been shown to be of prognostic relevance in ESFT. However, no conclusive results have been reported. We analyzed the clinicopathological significance of relevant cell cycle regulators in genetically confirmed ESFT. A total of 324 cases were analyzed for the immunohistochemical expression of p53, p21Waf1/Cip1, p27Kip1 and Ki67 and the chromosomal alterations of the p53 and 9p21 locus by fluorescent in situ hybridization. We observed that expression of p53 (p = 0.025), p21Waf1/Cip1 (p = 0.015) and p27Kip1 (p = 0.013) was higher in disseminated than in localized disease. Furthermore, a cohort of 217 patients with localized disease was considered for studying the prognosis involvement of these factors on patient follow‐up. The median follow‐up was 39 months (range: 0.17–452) with an overall survival (OS) of 55%. Ki67 was expressed in 34% of cases and constituted an independent prognostic factor for progression free survival and OS independently of the type of treatment [hazard ratio of 2.0 (95% CI: 1.3–3.1; p = 0.003) and 1.9 (95% IC: 1.3–2.9; p = 0.007) for progression free survival and OS, respectively, being especially relevant in the group of patients which incorporated radiotherapy in their regimen schedules. In conclusion, this study demonstrates that Ki67 expression constitutes a valuable indicator of poor prognosis in localized ESFT.

MicroRNAs: Promising New Antiangiogenic Targets in Cancer

MicroRNAs are one class of small, endogenous, non-coding RNAs that are approximately 22 nucleotides in length; they are very numerous, have been phylogenetically conserved, and involved in biological processes such as development, differentiation, cell proliferation, and apoptosis. MicroRNAs contribute to modulating the expression levels of specific proteins based on sequence complementarity with their target mRNA molecules and so they play a key role in both health and disease. Angiogenesis is the process of new blood vessel formation from preexisting ones, which is particularly relevant to cancer and its progression. Over the last few years, microRNAs have emerged as critical regulators of signalling pathways in multiple cell types including endothelial and perivascular cells. This review summarises the role of miRNAs in tumour angiogenesis and their potential implications as therapeutic targets in cancer.

The many faces of atypical Ewing’s sarcoma. A true entity mimicking sarcomas, carcinomas and lymphomas

Ewing’s sarcoma family of tumours (ESFT) comprises a group of small round cell tumours (SRCT) genetically defined by specific chromosomal translocations resulting in a fusion of the EWSR1 gene with a member of the ETS family of transcription factors. Atypical ESFT are the most challenging of the ESFT subtypes, and the differential diagnosis with other SRCT of bone and soft tissue is difficult since these subtypes can resemble other neoplasms. The present article describes nine cases of genetically confirmed, atypical ESFT, having unusual alterations at morphological and immunohistochemical (IHC) levels associated with atypical clinical presentation mimicking sarcomas, carcinomas and lymphomas. Present results demonstrate that ESFT showing overlapping morphological and immunohistochemical features with other SRCT of soft tissue and bone, or even with carcinomas or lymphoma, can be differentiated using molecular techniques. In SRCT with EWSR1 translocation demonstrated by FISH, the RT-PCR analysis of specific sarcoma-related gene fusion can offer important clues for the diagnosis of specific entities, especially in tumours with unusual histopathology and/or IHC findings. Thus, we confirm that the integration of clinical, histopathological, IHC and genetic data becomes decisive in the diagnosis of bone and soft tissue sarcomas.

Superficial Ewing's sarcoma family of tumors: a clinicopathological study with differential diagnoses

Background: Superficial/cutaneous Ewings sarcoma family of tumors (ESFT) are rare and have a relatively favorable prognosis compared with deep‐seated tumors. The aim of the present study is to describe the clinicopathological characteristics of six genetically confirmed ESFT presenting a superficial location.

An integrated analysis of miRNA and gene copy numbers in xenografts of Ewing's sarcoma

BackgroundXenografts have been shown to provide a suitable source of tumor tissue for molecular analysis in the absence of primary tumor material. We utilized ES xenograft series for integrated microarray analyses to identify novel biomarkers.MethodMicroarray technology (array comparative genomic hybridization (aCGH) and micro RNA arrays) was used to screen and identify copy number changes and differentially expressed miRNAs of 34 and 14 passages, respectively. Incubated cells used for xenografting (Passage 0) were considered to represent the primary tumor. Four important differentially expressed miRNAs (miR-31, miR-31*, miR-145, miR-106) were selected for further validation by real time polymerase chain reaction (RT-PCR). Integrated analysis of aCGH and miRNA data was performed on 14 xenograft passages by bioinformatic methods.ResultsThe most frequent losses and gains of DNA copy number were detected at 9p21.3, 16q and at 8, 15, 17q21.32-qter, 1q21.1-qter, respectively. The presence of these alterations was consistent in all tumor passages. aCGH profiles of xenograft passages of each series resembled their corresponding primary tumors (passage 0). MiR-21, miR-31, miR-31*, miR-106b, miR-145, miR-150*, miR-371-5p, miR-557 and miR-598 showed recurrently altered expression. These miRNAS were predicted to regulate many ES-associated genes, such as genes of the IGF1 pathway, EWSR1, FLI1 and their fusion gene (EWS-FLI1). Twenty differentially expressed miRNAs were pinpointed in regions carrying altered copy numbers.ConclusionIn the present study, ES xenografts were successfully applied for integrated microarray analyses. Our findings showed expression changes of miRNAs that were predicted to regulate many ES associated genes, such as IGF1 pathway genes, FLI1, EWSR1, and the EWS-FLI1 fusion genes.

Inflammatory fibroid polyp of the small bowel with a mutation in exon 12 of PDGFRα

Inflammatory fibroid polyp (IFP) is a benign reactive uncommon submucosal lesion of the gastrointestinal tract, the small intestine being the most common site of origin. Histologically, IFPs are characterized by spindle cells, a heavy inflammatory infiltrate including eosinophils and onion-sheet-like formation of lesional cells around blood vessels. We present a case report of an IFP harboring an activation mutation in the PDGFRα gene. The lesion was positive for CD34, PDGFRα, and p-PDGFRα immunostaining but was negative for c-KIT and desmin. After a sequencing analysis of KIT and PDGFRα, a mutation consisting of an in-frame deletion of codons 567-571 and a missense mutation in codon 566 (S566R) of PDGFRα was observed. This mutation could activate key cellular pathways with involvement in the pathogenesis of this entity. We concluded that more studies are necessary in order to clarify if this finding is a biologically distinct behavior or, on the contrary, represents a specific feature of the IFP.

Profile of the Roche cobas(®) EGFR mutation test v2 for non-small cell lung cancer.

ABSTRACT Introduction: The discovery of driver mutations in non-small cell lung cancer (NSCLC) has led to the development of genome-based personalized medicine. Fifteen to 20% of adenocarcinomas harbor an epidermal growth factor receptor (EGFR) activating mutation associated with responses to EGFR tyrosine kinase inhibitors (TKIs). Individual laboratories’ expertise and the availability of appropriate equipment are valuable assets in predictive molecular pathology, although the choice of methods should be determined by the nature of the samples to be tested and whether the detection of only well-characterized EGFR mutations or rather, of all detectable mutations, is required. Areas covered: The EGFR mutation testing landscape is manifold and includes both screening and targeted methods, each with their own pros and cons. Here we review one of these companion tests, the Roche cobas® EGFR mutation test v2, from a methodological point of view, also exploring its liquid-biopsy applications. Expert commentary: The Roche cobas® EGFR mutation test v2, based on real time RT-PCR, is a reliable option for testing EGFR mutations in clinical practice, either using tissue-derived DNA or plasma-derived cfDNA. This application will be valuable for laboratories with whose purpose is purely diagnostic and lacking high-throughput technologies.

Evaluation of Prognostic Factors and Their Capacity to Predict Biological Behavior in Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are c-KIT-signaling-driven mesenchymal tumors of the human digestive tract, many of which have c-KIT or PDGFRα activating mutations. The authors studied the immunohistochemical markers, c-KIT and PDGFRα mutations, in GISTs and their association with the clinicopathological and clinical follow-up in 145 GISTs. Tumors were located mainly in the stomach, the median tumor size being 7.5 cm. The mitotic index was ≤5 mitoses per 50 high-power fields in 61% of cases, 96% expressed CD117, and c-KIT or PDGFRα mutations were detected in 68% of cases. The median follow-up of the series was 52 months (range = 1 to 244.9 months). Tumor size, cell morphology, mitotic index, incomplete resection, Fletcher’s risk classification, Ki-67 overexpression, and c-KIT mutations were associated with progression-free survival. Incomplete resection and mitotic activity also provide information about overall survival. In conclusion, complete clinicopathological, immunohistochemical, and genetic descriptions are necessary to characterize this disease and optimize its clinical management.

Characterization of a New Human Cell Line (CH-3573) Derived from a Grade II Chondrosarcoma with Matrix Production

Chondrosarcomas are malignant cartilage-forming tumors that represent the third most common malignant solid tumor of bone. In patients with grades II and III, local recurrence, increasing tumor size and dedifferentiation have been associated with lower survival rates. These biologically poorly-understood neoplasms vary considerably in clinical presentation and biological behavior. Cytogenetic studies have shown that heterogeneity is related to karyotypic complexity; moreover, alterations in the 9p21 locus and TP53 gene are related to disease progression. Despite the relatively high frequency of chondrosarcoma only a limited number of cell lines exist in the scientific community, limiting the possibility to study hypothesis-derived research or primary drug interaction necessary for pre-clinical studies. We report a chondrosarcoma cell line, CH-3573, derived from a primary tumor that may serve as a useful tool for both in vitro and in vivo models to study the molecular pathogenesis. In addition, xenograft passages in nude mice were studied to characterize the genetic stability over the course of tumor progression. In contrary to other reported cell lines, an important feature of our established cell line was the retained matrix production, a characteristic feature of a conventional grade II chondrosarcoma. The cell line (CH-3573) was characterized by pathological, immunohistochemical and molecular genetic methods.