title: Gene expression profiling identifies different sub-types of retinoblastoma.
abstract: BACKGROUND
  Mutation of the RB1 gene is necessary but not sufficient for the development of retinoblastoma. The nature of events occurring subsequent to RB1 mutation is unclear, as is the retinal cell-of-origin of this tumour.
  
  
  METHODS
  Gene expression profiling of 21 retinoblastomas was carried out to identify genetic events that contribute to tumorigenesis and to obtain information about tumour histogenesis.
  
  
  RESULTS
  Expression analysis showed a clear separation of retinoblastomas into two groups. Group 1 retinoblastomas express genes associated with a range of different retinal cell types, suggesting derivation from a retinal progenitor cell type. Recurrent chromosomal alterations typical of retinoblastoma, for example, chromosome 1q and 6p gain and 16q loss were also a feature of this group, and clinically they were characterised by an invasive pattern of tumour growth. In contrast, group 2 retinoblastomas were found to retain many characteristics of cone photoreceptor cells and appear to exploit the high metabolic capacity of this cell type in order to promote tumour proliferation.
  
  
  CONCLUSIONS
  Retinoblastoma is a heterogeneous tumour with variable biology and clinical characteristics.
authors.affiliation: School of Cancer Sciences, Vincent Drive, University of Birmingham, Birmingham, UK.
authors.forename: G
authors.initials: G
authors.lastname: Kapatai
authors.forename: M-A
authors.initials: MA
authors.lastname: Brundler
authors.forename: H
authors.initials: H
authors.lastname: Jenkinson
authors.forename: P
authors.initials: P
authors.lastname: Kearns
authors.forename: M
authors.initials: M
authors.lastname: Parulekar
authors.forename: A C
authors.initials: AC
authors.lastname: Peet
authors.forename: C M
authors.initials: CM
authors.lastname: McConville
mesh_terms: D000328:Adult; D016000:Cluster Analysis; D055028:Comparative Genomic Hybridization; D020732:Cytogenetic Analysis; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D053263:Gene Regulatory Networks / Q000235:genetics; D006801:Humans; D046228:Microarray Analysis; D008954:Models, Biological; D012160:Retina / Q000378:metabolism; D019572:Retinal Neoplasms / Q000145:classification* / Q000235:genetics* / Q000473:pathology; D012175:Retinoblastoma / Q000145:classification* / Q000235:genetics* / Q000473:pathology