title: A Retrospective Analysis of Ki-67 Index and its Prognostic Significance in Over 800 Primary Breast Cancer Cases.
abstract: The Ki-67 index is chiefly important for distinguishing between luminal A and luminal B human epidermal growth factor receptor 2 (HER2neu)-negative breast cancer subtypes. However, its ability to predict response to chemotherapy is uncertain.
  
  
  
  Patients treated for primary breast cancer at the University Hospital of Cologne were identified. Immunohistochemistry for Ki-67 detection was performed according to standard protocols. Kaplan-Meier survival curves were calculated and compared using the log-rank test.
  
  
  
  Patients with low Ki-67 index had a significantly better disease-free-survival (DFS) than patients with high Ki-67 index (hazard ratio=2.85; 95% confidence interval=1.45-5.59; p=0.002). A significant influence on DFS was demonstrated (hazard ratio(HR)=1.02; confidence interval(CI)=1.00-1.04; p=0.048) within the subgroup of hormone receptor-positive and HER2neu-negative patients, but not within the subgroup of those with luminal B/HER2neu-negative tumors (DFS: p=0.801; overall-survival: p=0.379).
  
  
  
  The Ki-67 index has a prognostic impact on DFS in patients with hormone receptor-positive and HER2neu-negative tumors. The strict cut-off value was not suitable for distinguishing between high- and low-risk patients and their response to adjuvant chemotherapy.
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Cologne, Cologne, Germany Fabinshy.Thangarajah@uk-koeln.de.
authors.forename: Fabinshy
authors.initials: F
authors.lastname: Thangarajah
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Insa
authors.initials: I
authors.lastname: Enninga
authors.affiliation: Breast Center, University Hospital of Cologne, Cologne, Germany.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Malter
authors.affiliation: Institute of Medical Statistics, Informatics and Epidemiology, University of Cologne, Cologne, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Hamacher
authors.affiliation: Department of Pathology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Birgid
authors.initials: B
authors.lastname: Markiefka
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Richters
authors.affiliation: Breast Center, Helios Clinic Krefeld, Krefeld, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Krämer
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Mallmann
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital of Cologne, Cologne, Germany.|Breast Center, University Hospital of Cologne, Cologne, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Kirn
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D019394:Ki-67 Antigen / Q000378:metabolism*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012189:Retrospective Studies; D015996:Survival Rate
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
keywords: IHC; Ki-67 index; Predictive factors; prognosis