title: A Comparison of the Hot Spot and the Average Cancer Cell Counting Methods and the Optimal Cutoff Point of the Ki-67 Index for Luminal Type Breast Cancer.
abstract: OBJECTIVE
  In this case-control study, we investigated the most suitable cell counting area and the optimal cutoff point of the Ki-67 index.
  
  
  METHODS
  Thirty recurrent cases were selected among hormone receptor (HR)-positive/HER2-negative breast cancer patients. As controls, 90 nonrecurrent cases were randomly selected by allotting 3 controls to each recurrent case based on the following criteria: age, nodal status, tumor size, and adjuvant endocrine therapy alone. Both the hot spot and the average area of the tumor were evaluated on a Ki-67 immunostaining slide.
  
  
  RESULTS
  The median Ki-67 index value at the hot spot and average area were 25.0 and 14.5%, respectively. Irrespective of the area counted, the Ki-67 index value was significantly higher in all of the recurrent cases (p < 0.0001). The multivariate analysis revealed that the Ki-67 index value of 20% at the hot spot was the most suitable cutoff point for predicting recurrence. Moreover, higher x0394;Ki-67 index value (the difference between the hot spot and the average area, ≥10%) and lower progesterone receptor expression (<20%) were significantly correlated with recurrence.
  
  
  CONCLUSIONS
  A higher Ki-67 index value at the hot spot strongly correlated with recurrence, and the optimal cutoff point was found to be 20%.
authors.affiliation: Department of Pathology, Kumamoto Shinto General Hospital, Kumamoto, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Arima
authors.forename: Reiki
authors.initials: R
authors.lastname: Nishimura
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Osako
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: Mamiko
authors.initials: M
authors.lastname: Fujisue
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Okumura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakano
authors.forename: Rumiko
authors.initials: R
authors.lastname: Tashima
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Toyozumi
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000737:chemistry* / Q000175:diagnosis* / Q000473:pathology; D016022:Case-Control Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis*; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000737:chemistry* / Q000175:diagnosis*; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone