title: Flow cytometric phenotype of rhabdomyosarcoma bone marrow metastatic cells and its implication in differential diagnosis with neuroblastoma.
abstract: BACKGROUND
  The goal of this study was to develop a flow cytometric (FCM) method for assessing the presence of metastatic cells in bone marrow (BM) and peripheral blood (PB) obtained from rhabdomysarcoma (RMS) patients. Myogenin (Myf4), a specific molecular RMS marker, was also investigated in the same samples. Since neuroblastoma (NB) metastasizes to the BM, the potential application of cytometry in differential diagnosis was explored.
  
  
  METHODS
  CD45, CD56, CD90 and CD57 antibodies were used in 7 paired BM and PB samples (from 7 RMS stage IV patients at presentation), 23 BM samples (from 13 RMS stage I and II patients at presentation), and ten paired BM and PB samples taken at presentation and five BM samples taken at recurrence from 13 NB stage 4 patients.
  
  
  RESULTS
  All seven BM samples from RMS stage IV (but not those from patients with localized disease) showed both the CD45- CD56+ phenotype and the Myf4 transcript. Four cases also showed CD90 and two CD57 positivity. Neither the CD45- CD56+ phenotype, nor Myf4 were recorded in the BM and PB samples from patients with localized disease. All the NB BM samples (15/15) showed the CD45- CD56+ CD90+ phenotype and 10/15 also showed CD57 positivity. Only 3/10 blood samples from the NB patients revealed tumor cells.
  
  
  CONCLUSIONS
  CD45, CD56, CD90 and CD57 antibodies can be used in FCM for marrow metastasis detection in both, RMS and NB patients.
authors.affiliation: Department of Anatomic Pathology, Experimental Molecular Pathology Unit, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy. fabio.bozzi@istitutotumori.mi.it
authors.forename: Fabio
authors.initials: F
authors.lastname: Bozzi
authors.forename: Paola
authors.initials: P
authors.lastname: Collini
authors.forename: Antonella
authors.initials: A
authors.lastname: Aiello
authors.forename: Elena
authors.initials: E
authors.lastname: Barzanò
authors.forename: Felicita
authors.initials: F
authors.lastname: Gambirasio
authors.forename: Marta
authors.initials: M
authors.lastname: Podda
authors.forename: Cristina
authors.initials: C
authors.lastname: Meazza
authors.forename: Andrea
authors.initials: A
authors.lastname: Ferrari
authors.forename: Roberto
authors.initials: R
authors.lastname: Luksch
mesh_terms: D019046:Bone Marrow Neoplasms / Q000097:blood / Q000235:genetics / Q000556:secondary*; D003937:Diagnosis, Differential; D005434:Flow Cytometry; D006801:Humans; D009367:Neoplasm Staging; D009360:Neoplastic Cells, Circulating / Q000473:pathology; D009447:Neuroblastoma / Q000097:blood / Q000175:diagnosis / Q000235:genetics / Q000473:pathology*; D010641:Phenotype; D012334:RNA, Neoplasm / Q000032:analysis; D012208:Rhabdomyosarcoma / Q000097:blood / Q000175:diagnosis / Q000235:genetics / Q000473:pathology*
chemical_list: D012334:RNA, Neoplasm