title: High ALK mRNA expression has a negative prognostic significance in rhabdomyosarcoma.
abstract: BACKGROUND
  Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase aberrantly expressed in cancer, but its clinical and functional importance remain controversial. Mutation or amplification of ALK, as well as its expression levels assessed by conventional immunohistochemistry methods, has been linked to prognosis in cancer, although with potential bias because of the semi-quantitative approaches. Herein, we measured ALK mRNA expression in rhabdomyosarcoma (RMS) and determined its clinical impact on patients' stratification and outcome.
  
  
  METHODS
  Specimens were obtained from RMS patients and cell lines, and ALK expression was analysed by quantitative RT-PCR, western blotting, IHC, and copy number analysis.
  
  
  RESULTS
  High ALK mRNA expression was detected in the vast majority of PAX3/7-FOXO1-positive tumours, whereas PAX3/7-FOXO1-negative RMS displayed considerably lower amounts of both mRNA and protein. Notably, ALK mRNA distinguished unfavourable PAX3/7-FOXO1-positive tumours from PAX3/7-FOXO1-negative RMS (P<0.0001), and also correlated with larger tumour size (P<0.05) and advanced clinical stage (P<0.01), independently of fusion gene status. High ALK mRNA levels were of prognostic relevance by Cox univariate regression analysis and correlated with increased risk of relapse (P=0.001) and survival (P=0.01), whereas by multivariate analysis elevated ALK mRNA expression resulted a negative prognostic marker when clinical stage was not included.
  
  
  CONCLUSIONS
  Quantitative assessment of ALK mRNA expression helps to improve risk stratification of RMS patients and identifies tumours with adverse biological characteristics and aggressive behaviour.
authors.affiliation: 1] Pediatric Onco-Haematology Clinic, University-Hospital of Padova, via Giustiniani 3, 35100 Padova, Italy [2] Institute of Pediatric Research Città della Speranza, 35100 Padova, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Bonvini
authors.forename: A
authors.initials: A
authors.lastname: Zin
authors.forename: R
authors.initials: R
authors.lastname: Alaggio
authors.forename: B
authors.initials: B
authors.lastname: Pawel
authors.forename: G
authors.initials: G
authors.lastname: Bisogno
authors.forename: A
authors.initials: A
authors.lastname: Rosolen
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D045744:Cell Line, Tumor; D002648:Child; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D011379:Prognosis; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics; D012208:Rhabdomyosarcoma / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D016019:Survival Analysis
chemical_list: D012333:RNA, Messenger; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases