title: High Ki-67 expression is a poor prognostic indicator of 5-year recurrence free survival in patients with invasive breast cancer.
abstract: OBJECTIVE
  Ki-67 is a biomarker that reflects the cell proliferation state. Despite a clear understanding of the protein's structure and properties, its functional role remains elusive. We conducted the present study to assess the prognostic value of Ki-67 in breast cancer (BC).
  
  
  METHODS
  We enrolled 164 individuals in this study: 30 patients with benign tumors and 134 with invasive BC. Immunohistochemistry (IHC) was used to detect Ki-67 expression The prognostic value of Ki-67 for 5-year recurrence-free survival (RFS) could be analyzed in 134 BC patients.
  
  
  RESULTS
  Ki-67 expression showed significant differences with the tumor grade, lymph node (LN) status, HER2 status and hormone receptor (HR) status (all P<0.05). When Ki- 67 11% was used as cutoff to divide the 134 cases into two groups, with high and low expression, the patients in former had a significantly higher 5-year recurrence rate (37.1% vs 8.1%, P=0.001) and a worse RFS (log-rank test, P=0.0017) than those in low Ki-67 expression group. Ki-67 was an independent prognostic predictor of 5-year RFS in both univariate and multivariate analyses.
  
  
  CONCLUSIONS
  Ki-67 can be used as a negative predictor of 5-year RFS of patients with invasive BC.
authors.affiliation: Department of Oncology, Zhongnan Hospital of Wuhan University, Hubei Key Laboratory on Tumor Biological Behavior and Hubei Cancer Clinical Study Center, Wuhan, China.
authors.forename: Xue-Qin
authors.initials: XQ
authors.lastname: Yang
authors.forename: Fu-Bing
authors.initials: FB
authors.lastname: Wang
authors.forename: Chuang
authors.initials: C
authors.lastname: Chen
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Peng
authors.forename: Jing-Fang
authors.initials: JF
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics / Q000401:mortality* / Q000473:pathology*; D049109:Cell Proliferation; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human