title: Distinct distribution and prognostic significance of molecular subtypes of breast cancer in Chinese women: a population-based cohort study.
abstract: BACKGROUND
  Molecular classification of breast cancer is an important prognostic factor. The distribution of molecular subtypes of breast cancer and their prognostic value has not been well documented in Asians.
  
  
  METHODS
  A total of 2,791 breast cancer patients recruited for a population-based cohort study were evaluated for molecular subtypes of breast cancer by immunohistochemical assays. Data on clinicopathological characteristics were confirmed by centralized pathology review. The average follow-up of the patients was 53.4 months. Overall and disease-free survival by molecular subtypes of breast cancer were evaluated.
  
  
  RESULTS
  The prevalence of the luminal A, luminal B, human epidermal growth factor receptor 2 (HER2), and triple-negative subtypes were 48.6%, 16.7%, 13.7%, and 12.9%, respectively. The luminal A subtype was more likely to be diagnosed in older women (P = 0.03) and had a stronger correlation with favorable clinicopathological factors (smaller tumor size, lower histologic grade, and earlier TNM stage) than the triple-negative or HER2 subtypes. Women with triple-negative breast cancer had a higher frequency of family history of breast cancer than women with other subtypes (P = 0.048). The 5-year overall/disease-free survival percentages for the luminal A, luminal B, HER2, and triple-negative subtypes were 92.9%/88.6%, 88.6%/85.1%, 83.2%/79.1%, and 80.7%/76.0%, respectively. A similar pattern was observed in multivariate analyses. Immunotherapy was associated with improved overall and disease-free survival for luminal A breast cancer, but reduced disease-free survival (HR = 2.21, 95% CI, 1.09-4.48) for the HER2 subtype of breast cancer.
  
  
  CONCLUSIONS
  The triple-negative and HER2 subtypes were associated with poorer outcomes compared with the luminal A subtype among these Chinese women. The HER2 subtype was more prevalent in this Chinese population compared with Western populations, suggesting the importance of standardized HER2 detection and anti-HER2 therapy to potentially benefit a high proportion of breast cancer patients in China.
authors.affiliation: Department of Medicine, Vanderbilt Epidemiology Center, Nashville, TN 37203-1738, USA.
authors.forename: Yinghao
authors.initials: Y
authors.lastname: Su
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Kai
authors.initials: K
authors.lastname: Gu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.forename: Guoliang
authors.initials: G
authors.lastname: Li
authors.forename: Qiuyin
authors.initials: Q
authors.lastname: Cai
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Xiao Ou
authors.initials: XO
authors.lastname: Shu
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D044466:Asian People; D001943:Breast Neoplasms / Q000145:classification / Q000208:ethnology / Q000378:metabolism*; D002681:China; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000706:statistics & numerical data; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D046888:Tissue Array Analysis / Q000706:statistics & numerical data
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone