title: Analysis of the MammaPrint breast cancer assay in a predominantly postmenopausal cohort.
abstract: OBJECTIVE
  Most node-negative breast cancer patients are older and postmenopausal and are increasingly being offered adjuvant chemotherapy despite their low overall risk of distant relapse. A molecular diagnostic test with high negative predictive value (NPV) for distant metastasis in this subgroup would spare many older breast cancer patients adjuvant treatment.
  
  
  METHODS
  We determined the NPV and positive predictive value of the MammaPrint assay in breast cancer patients who were consecutively diagnosed and treated at the Massachusetts General Hospital between 1985 and 1997. Primary tumors from 100 patients with node-negative, invasive breast cancer (median age, 62.5 years; median follow-up, 11.3 years) were subjected to MammaPrint analysis and classified as being at either low or high risk for distant metastasis.
  
  
  RESULTS
  The MammaPrint 70-gene signature displayed excellent NPV as in previous studies, correctly identifying 100% of women at low risk for distant metastases at 5 years. However, this assay had a lower positive predictive value (12% at 5 years) than previously observed.
  
  
  CONCLUSIONS
  The MammaPrint assay was originally designed to identify younger breast cancer patients at low risk for distant metastasis, who might consequently be spared systemic treatment. We show here that the same signature has a very high NPV for distant recurrence after adjuvant treatment in older breast cancer patients.
authors.affiliation: Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA.
authors.forename: Ben S
authors.initials: BS
authors.lastname: Wittner
authors.forename: Dennis C
authors.initials: DC
authors.lastname: Sgroi
authors.forename: Paula D
authors.initials: PD
authors.lastname: Ryan
authors.forename: Tako J
authors.initials: TJ
authors.lastname: Bruinsma
authors.forename: Annuska M
authors.initials: AM
authors.lastname: Glas
authors.forename: Anitha
authors.initials: A
authors.lastname: Male
authors.forename: Sonika
authors.initials: S
authors.lastname: Dahiya
authors.forename: Karleen
authors.initials: K
authors.lastname: Habin
authors.forename: Rene
authors.initials: R
authors.lastname: Bernards
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Haber
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Van't Veer
authors.forename: Sridhar
authors.initials: S
authors.lastname: Ramaswamy
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000145:classification* / Q000235:genetics* / Q000401:mortality; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D017698:Postmenopause / Q000235:genetics*; D011237:Predictive Value of Tests