title: Multicenter validation of a gene expression-based prognostic signature in lymph node-negative primary breast cancer.
abstract: OBJECTIVE
  We previously identified in a single-center study a 76-gene prognostic signature for lymph node-negative (LNN) breast cancer patients. The aim of this study was to validate this gene signature in an independent more diverse population of LNN patients from multiple institutions.
  
  
  METHODS
  Using custom-designed DNA chips we analyzed the expression of the 76 genes in RNA of frozen tumor samples from 180 LNN patients who did not receive adjuvant systemic treatment.
  
  
  RESULTS
  In this independent validation, the 76-gene signature was highly informative in identifying patients with distant metastasis within 5 years (hazard ratio, [HR], 7.41; 95% CI, 2.63 to 20.9), even when corrected for traditional prognostic factors in multivariate analysis (HR, 11.36; 95% CI, 2.67 to 48.4). The actuarial 5- and 10-year distant metastasis-free survival were 96% (95% CI, 89% to 99%) and 94% (95% CI, 83% to 98%), respectively, for the good profile group and 74% (95% CI, 64% to 81%) and 65% (53% to 74%), respectively for the poor profile group. The sensitivity for 5-yr distant metastasis-free survival was 90%, and the specificity was 50%. The positive and negative predictive values were 38% (95% CI, 29% to 47%) and 94% (95% CI, 86% to 97%), respectively. The 76-gene signature was confirmed as a strong prognostic factor in subgroups of estrogen receptor-positive patients, pre- and postmenopausal patients, and patients with tumor sizes 20 mm or smaller. The subgroup of patients with estrogen receptor-negative tumors was considered too small to perform a separate analysis.
  
  
  CONCLUSIONS
  Our data provide a strong methodologic and clinical multicenter validation of the predefined prognostic 76-gene signature in LNN breast cancer patients.
authors.affiliation: Department of Medical Oncology, Erasmus Medical Center, Daniel den Hoed Cancer Center, Rotterdam, The Netherlands. j.foekens@erasmusmc.nl
authors.forename: John A
authors.initials: JA
authors.lastname: Foekens
authors.forename: David
authors.initials: D
authors.lastname: Atkins
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Fred C G J
authors.initials: FC
authors.lastname: Sweep
authors.forename: Nadia
authors.initials: N
authors.lastname: Harbeck
authors.forename: Angelo
authors.initials: A
authors.lastname: Paradiso
authors.forename: Tanja
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authors.lastname: Cufer
authors.forename: Anieta M
authors.initials: AM
authors.lastname: Sieuwerts
authors.forename: Dmitri
authors.initials: D
authors.lastname: Talantov
authors.forename: Paul N
authors.initials: PN
authors.lastname: Span
authors.forename: Vivianne C G
authors.initials: VC
authors.lastname: Tjan-Heijnen
authors.forename: Alfredo F
authors.initials: AF
authors.lastname: Zito
authors.forename: Katja
authors.initials: K
authors.lastname: Specht
authors.forename: Heinz
authors.initials: H
authors.lastname: Hoefler
authors.forename: Rastko
authors.initials: R
authors.lastname: Golouh
authors.forename: Francesco
authors.initials: F
authors.lastname: Schittulli
authors.forename: Manfred
authors.initials: M
authors.lastname: Schmitt
authors.forename: Louk V A M
authors.initials: LV
authors.lastname: Beex
authors.forename: Jan G M
authors.initials: JG
authors.lastname: Klijn
authors.forename: Yixin
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008875:Middle Aged; D016019:Survival Analysis