title: CXCL14, CXCR7 expression and CXCR4 splice variant ratio associate with survival and metastases in Ewing sarcoma patients.
abstract: OBJECTIVE
  Ewing sarcoma (EWS) is the second most common sarcoma of bone in children and young adults. Patients with disseminated disease at diagnosis or early relapse have a poor prognosis. Our goal was to identify novel predictive biomarkers for these patients, focusing on chemokines, specifically genes involved in the CXCR4-pathway because of their established role in metastasis and tumour growth.
  
  
  METHODS
  Total RNA isolated from therapy-naïve tumour samples (n=18; panel I) and cell lines (n=21) was used to study expression of CXCR4-pathway related genes and CXCR4 splice variants (CXCR4-2: Small and CXCR4-1: Large) by RT-Q-PCR. Expression levels were correlated to overall survival (OS) and event free survival (EFS). Study results were validated in an independent series of 26 tumour samples (panel II) from therapy-naïve tumour samples.
  
  
  RESULTS
  CXCL12, CXCR4, CXCR7 and CXCL14 were expressed and high CXCR7 and CXCL14 expression showed a positive correlation with EFS and OS and a negative correlation with metastasis development. Both splice variants CXCR4 were expressed in cell lines and tumour samples and CXCR4-1/CXCR4-2 ratio was significantly higher in tumour samples compared to cell lines and correlated with an improved EFS and OS. The results from the test panel were validated in an independent sample panel.
  
  
  CONCLUSIONS
  We identified a set of genes involved in CXCR4 signalling that may be used as a marker to predict survival and metastasis development in Ewing sarcoma.
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: L G L
authors.initials: LG
authors.lastname: Sand
authors.affiliation: Laboratorio di Ricerca Oncologica, Orthopedic Institute Rizzoli, Italy.
authors.forename: K
authors.initials: K
authors.lastname: Scotlandi
authors.affiliation: Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Berghuis
authors.affiliation: Department of Molecular Cell Biology, Institute of Biology Leiden, Leiden, The Netherlands.
authors.forename: B E
authors.initials: BE
authors.lastname: Snaar-Jagalska
authors.affiliation: Laboratorio di Ricerca Oncologica, Orthopedic Institute Rizzoli, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Picci
authors.affiliation: Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, Leiden, The Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Schmidt
authors.affiliation: Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Szuhai
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: P.C.W.Hogendoorn@lumc.nl.
authors.forename: P C W
authors.initials: PC
authors.lastname: Hogendoorn
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D054377:Chemokine CXCL12 / Q000235:genetics; D019743:Chemokines, CXC / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D020033:Protein Isoforms / Q000235:genetics; D012326:RNA Splicing; D054387:Receptors, CXCR / Q000235:genetics*; D019718:Receptors, CXCR4 / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012512:Sarcoma, Ewing / Q000235:genetics* / Q000473:pathology; D015398:Signal Transduction / Q000235:genetics; D055815:Young Adult
chemical_list: C501896:ACKR3 protein, human; C515255:CXCL12 protein, human; C118056:CXCL14 protein, human; C527276:CXCR4 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D020033:Protein Isoforms; D054387:Receptors, CXCR; D019718:Receptors, CXCR4
keywords: Biomarker; Molecular targeted therapy; Splice variant; Tumour microenvironment