title: Gene expression signatures in breast cancer distinguish phenotype characteristics, histologic subtypes, and tumor invasiveness.
abstract: BACKGROUND
  The development of reliable gene expression profiling technology is having an increasing impact on the understanding of breast cancer biology.
  
  
  METHODS
  In this study, microarray analysis was performed to establish gene signatures for different breast cancer phenotypes, to determine differentially expressed gene sequences at different stages of the disease, and to identify sequences with biologic significance for tumor progression. Samples were taken from patients before their treatment. After microarray analysis, the expression level of 153 selected genes was studied by real-time quantitative polymerase chain reaction analysis.
  
  
  RESULTS
  Several gene sequences were expressed differentially in tumor samples versus control samples and also were associated with different breast cancer phenotypes, estrogen receptor status, tumor histology, and grade of tumor differentiation. In lymph node-negative tumors were identified a set of genes related to tumor differentiation grade.
  
  
  CONCLUSIONS
  Several differentially expressed gene sequences were identified at different stages of breast cancer.
authors.affiliation: Department of Radiation Oncology, University of Granada School of Medicine, 18012 Granada, Spain.
authors.forename: Vincente
authors.initials: V
authors.lastname: Pedraza
authors.forename: Jose A
authors.initials: JA
authors.lastname: Gomez-Capilla
authors.forename: Georgia
authors.initials: G
authors.lastname: Escaramis
authors.forename: Carolina
authors.initials: C
authors.lastname: Gomez
authors.forename: Pablo
authors.initials: P
authors.lastname: Torné
authors.forename: Jose M
authors.initials: JM
authors.lastname: Rivera
authors.forename: Angel
authors.initials: A
authors.lastname: Gil
authors.forename: Patricia
authors.initials: P
authors.lastname: Araque
authors.forename: Nicolas
authors.initials: N
authors.lastname: Olea
authors.forename: Xavier
authors.initials: X
authors.lastname: Estivill
authors.forename: M Esther
authors.initials: ME
authors.lastname: Fárez-Vidal
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D003628:Database Management Systems; D018450:Disease Progression; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D053858:Metabolic Networks and Pathways; D009367:Neoplasm Staging; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D054928:Validation Studies as Topic
chemical_list: D014408:Biomarkers, Tumor