title: Neuroblastoma messenger RNA is frequently detected in bone marrow at diagnosis of localised neuroblastoma patients.
abstract: BACKGROUND
  The clinical importance of the detection of neuroblastoma messenger RNA (mRNA) in bone marrow (BM) of localised neuroblastoma patients at diagnosis remains unclear. In this prospective multicentre study, BM samples of a large cohort, were studied using real-time quantitative polymerase chain reaction (qPCR).
  
  
  METHODS
  BM samples at diagnosis from 160 patients with localised neuroblastoma were prospectively collected at Dutch and German centres between 2009 and 2013. qPCR was performed using five neuroblastoma specific markers. The association with other biological factors and the prognostic impact of BM positivity and clinical response was assessed.
  
  
  RESULTS
  In 58 out of 160 patients neuroblastoma mRNA was detected in BM. In 47 of the 58 positive samples only one marker was found positive. BM positivity was significantly associated with MYCN amplification (p = 0.02) and deletion of chromosome 1p (p = 0.04). In total 31 patients had an event, of which only five patients had progression to stage IV. BM positivity was not associated with an unfavourable outcome. However, the detection of more than one marker was associated with an unfavourable outcome (systemic or local relapse) (event free survival 48% versus 85%; p = 0.03) in the whole cohort and in the observation group.
  
  
  CONCLUSIONS
  BM positivity was associated with unfavourable biological factors and might represent more aggressive tumours. Patients with qPCR positive BM should not be upstaged, because of very few systemic events in the cohort. However, for patients with more than one marker positive a more careful follow-up is advisable. These results need to be verified in a very large cohort of localised patients.
authors.affiliation: Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory of the AMC, University of Amsterdam, Amsterdam, The Netherlands; Department of Pediatric Oncology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: Esther M
authors.initials: EM
authors.lastname: van Wezel
authors.affiliation: Children's Hospital, University of Cologne, Pediatric Hematology and Oncology, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Decarolis
authors.affiliation: Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory of the AMC, University of Amsterdam, Amsterdam, The Netherlands; Department of Pediatric Oncology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: Janine
authors.initials: J
authors.lastname: Stutterheim
authors.affiliation: Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory of the AMC, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Lily
authors.initials: L
authors.lastname: Zappeij-Kannegieter
authors.affiliation: Children's Hospital, University of Cologne, Pediatric Hematology and Oncology, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Berthold
authors.affiliation: Children's Hospital, University of Cologne, Pediatric Hematology and Oncology, Germany.
authors.forename: Roswitha
authors.initials: R
authors.lastname: Schumacher-Kuckelkorn
authors.affiliation: Children's Hospital, University of Cologne, Pediatric Hematology and Oncology, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Simon
authors.affiliation: Department of Biostatistics, Leiden University Medical Center and Dutch Childhood Oncology Group, The Hague, The Netherlands.
authors.forename: Marta
authors.initials: M
authors.lastname: Fiocco
authors.affiliation: Department of Pediatric Oncology, Sophia Children's Hospital, Erasmus Medical Center, Rotterdam, The Netherlands; Prinses Máxima Centrum, Utrecht, The Netherlands.
authors.forename: Max M
authors.initials: MM
authors.lastname: van Noesel
authors.affiliation: Department of Pediatric Oncology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: Huib N
authors.initials: HN
authors.lastname: Caron
authors.affiliation: Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory of the AMC, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: C Ellen
authors.initials: CE
authors.lastname: van der Schoot
authors.affiliation: Children's Hospital, University of Cologne, Pediatric Hematology and Oncology, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Hero
authors.affiliation: Department of Pediatric Oncology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, The Netherlands; Prinses Máxima Centrum, Utrecht, The Netherlands. Electronic address: g.a.tytgat@amc.uva.nl.
authors.forename: Godelieve A M
authors.initials: GAM
authors.lastname: Tytgat
mesh_terms: D000293:Adolescent; D014408:Biomarkers, Tumor / Q000235:genetics*; D001853:Bone Marrow / Q000737:chemistry*; D001856:Bone Marrow Examination; D002648:Child; D002675:Child, Preschool; D002872:Chromosome Deletion; D002878:Chromosomes, Human, Pair 1; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D005784:Gene Amplification; D020022:Genetic Predisposition to Disease; D005858:Germany; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053208:Kaplan-Meier Estimate; D008297:Male; D000071447:N-Myc Proto-Oncogene Protein; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D009426:Netherlands; D009447:Neuroblastoma / Q000235:genetics* / Q000401:mortality / Q000556:secondary / Q000628:therapy; D009687:Nuclear Proteins / Q000235:genetics; D015513:Oncogene Proteins / Q000235:genetics; D010641:Phenotype; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012333:RNA, Messenger / Q000235:genetics*; D012334:RNA, Neoplasm / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; C459801:MYCN protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm
keywords: Bone marrow; Localised; Minimal disease; Neuroblastoma; Real-time quantitative PCR