title: Early detection of breast cancer based on gene-expression patterns in peripheral blood cells.
abstract: BACKGROUND
  Existing methods to detect breast cancer in asymptomatic patients have limitations, and there is a need to develop more accurate and convenient methods. In this study, we investigated whether early detection of breast cancer is possible by analyzing gene-expression patterns in peripheral blood cells.
  
  
  METHODS
  Using macroarrays and nearest-shrunken-centroid method, we analyzed the expression pattern of 1,368 genes in peripheral blood cells of 24 women with breast cancer and 32 women with no signs of this disease. The results were validated using a standard leave-one-out cross-validation approach.
  
  
  RESULTS
  We identified a set of 37 genes that correctly predicted the diagnostic class in at least 82% of the samples. The majority of these genes had a decreased expression in samples from breast cancer patients, and predominantly encoded proteins implicated in ribosome production and translation control. In contrast, the expression of some defense-related genes was increased in samples from breast cancer patients.
  
  
  CONCLUSIONS
  The results show that a blood-based gene-expression test can be developed to detect breast cancer early in asymptomatic patients. Additional studies with a large sample size, from women both with and without the disease, are warranted to confirm or refute this finding.
authors.affiliation: DiaGenic ASA, Oslo, Norway. praveen.sharma@diagenic.com
authors.forename: Praveen
authors.initials: P
authors.lastname: Sharma
authors.forename: Narinder S
authors.initials: NS
authors.lastname: Sahni
authors.forename: Robert
authors.initials: R
authors.lastname: Tibshirani
authors.forename: Per
authors.initials: P
authors.lastname: Skaane
authors.forename: Petter
authors.initials: P
authors.lastname: Urdal
authors.forename: Hege
authors.initials: H
authors.lastname: Berghagen
authors.forename: Marianne
authors.initials: M
authors.lastname: Jensen
authors.forename: Lena
authors.initials: L
authors.lastname: Kristiansen
authors.forename: Cecilie
authors.initials: C
authors.lastname: Moen
authors.forename: Pradeep
authors.initials: P
authors.lastname: Sharma
authors.forename: Alia
authors.initials: A
authors.lastname: Zaka
authors.forename: Jarle
authors.initials: J
authors.lastname: Arnes
authors.forename: Torill
authors.initials: T
authors.lastname: Sauer
authors.forename: Lars A
authors.initials: LA
authors.lastname: Akslen
authors.forename: Ellen
authors.initials: E
authors.lastname: Schlichting
authors.forename: Anne-Lise
authors.initials: AL
authors.lastname: Børresen-Dale
authors.forename: Anders
authors.initials: A
authors.lastname: Lönneborg
mesh_terms: D000704:Analysis of Variance; D001773:Blood Cells / Q000473:pathology*; D001943:Breast Neoplasms / Q000097:blood / Q000235:genetics* / Q000473:pathology*; D018076:DNA, Complementary / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D018076:DNA, Complementary; D004273:DNA, Neoplasm