title: Prognostic significance of molecular subtype in T1N0M0 breast cancer: Korean experience.
abstract: OBJECTIVE
  Gene expression profiling studies have identified several breast cancer subtypes associated with markedly different clinical outcomes. In general, patients with stage I breast cancer have excellent outcomes. We assessed the clinicopathological characteristics and outcomes of patients with T1N0M0 breast cancer according to molecular subtype.
  
  
  METHODS
  Seven hundred and sixty-two T1N0M0 breast cancer patients undergoing curative surgery between January 1990 and December 2007 were analyzed. Subtypes were classified according to hormone receptor (HR) and human epidermal growth factor receptor-2 (HER2) status as follows: HR+/HER2-, HR+/HER2+, HR-/HER2- (triple-negative, TN), and HR-/HER2+.
  
  
  RESULTS
  The distribution of subtypes was HR+/HER2-, 56.6%; HR+/HER2+, 10.1%; TN, 20.1%; and HR-/HER2+, 13.3%. Marked differences were observed among subtypes in multifocality/multicentricity, histological grade, extensive intraductal components, p53 expression and the Ki-67 index. There were differences in recurrence-free survival and overall survival among patients with different molecular subtypes (log-rank p < 0.001 and 0.024, respectively). By multivariate analysis, lymphovascular invasion and classification of molecular subtype were independent predictors of recurrence (p = 0.003 and 0.043, respectively). The TN subtype showed significantly worse recurrence-free survival compared to the HR+/HER2- subtype (hazard ratio, 4.54; 95% confidence interval, 1.60-12.86; p = 0.004).
  
  
  CONCLUSIONS
  Patients with T1N0M0 breast cancer, a group with generally favorable clinical outcomes, had prognoses that were associated with the molecular subtype. The TN subtype was an independent predictor for recurrence in patients with T1N0M0 breast cancer.
authors: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, 215-4 Gongneung-dong, Nowon-gu, 139-706 Seoul, Republic of Korea.
authors: R G
authors: RG
authors: Kim
authors: E K
authors: EK
authors: Kim
authors: H A
authors: HA
authors: Kim
authors: J S
authors: JS
authors: Koh
authors: M S
authors: MS
authors: Kim
authors: K I
authors: KI
authors: Kim
authors: J I
authors: JI
authors: Lee
authors: N M
authors: NM
authors: Moon
authors: E
authors: E
authors: Ko
authors: W C
authors: WC
authors: Noh