title: Metastatic potential of T1 breast cancer can be predicted by the 70-gene MammaPrint signature.
abstract: BACKGROUND
  Mammographic screening and increased awareness has led to an increase in the detection of T1 breast tumors that are generally estimated as having low risk of recurrence after locoregional treatment. However, even small tumors can metastasize, which leaves us with the question for the necessity of adjuvant treatment. Therefore, additional prognostic markers are needed to tailor adjuvant systemic treatment for these relatively low-risk patients. The aim of our study was to evaluate the accuracy of the 70-gene MammaPrint signature in T1 breast cancer.
  
  
  METHODS
  We selected 964 patients from previously reported studies with pT1 tumors (<or=2 cm). Frozen tumor samples were hybridized on the 70-gene signature array at the time of the initial study and classified as having good prognosis or poor prognosis.
  
  
  RESULTS
  The median follow-up was 7.1 years (range 0.2-25.2). The 10-year distant metastasis-free (DMFS) and breast cancer specific survival (BCSS) probabilities were 87% (SE 2%) and 91% (SE 2%), respectively, for the good prognosis-signature group (n = 525), and 72% (SE 3%) and 72% (SE 3%), respectively, for the poor prognosis-signature group (n = 439). The signature was an independent prognostic factor for BCSS at 10 years (multivariate hazard ratio [HR] 3.25 [95% confidence interval, CI, 1.92-5.51; P < .001]). Moreover, the 70-gene MammaPrint signature predicted DMFS at 10 years for 139 patients with pT1ab cancers (HR 3.45 [95% CI 1.04-11.50, P = .04]).
  
  
  CONCLUSIONS
  The 70-gene MammaPrint signature is an independent prognostic factor in patients with pT1 tumors and can help to individualize adjuvant treatment recommendation in this increasing breast cancer population.
authors.affiliation: Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
authors.forename: Stella
authors.initials: S
authors.lastname: Mook
authors.forename: Michael
authors.initials: M
authors.lastname: Knauer
authors.forename: Jolien M
authors.initials: JM
authors.lastname: Bueno-de-Mesquita
authors.forename: Valesca P
authors.initials: VP
authors.lastname: Retel
authors.forename: Jelle
authors.initials: J
authors.lastname: Wesseling
authors.forename: Sabine C
authors.initials: SC
authors.lastname: Linn
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Van't Veer
authors.forename: Emiel J
authors.initials: EJ
authors.lastname: Rutgers
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D018275:Carcinoma, Lobular / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008207:Lymphatic Metastasis; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D020411:Oligonucleotide Array Sequence Analysis; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone