title: Prognostic impact of discrepant Ki67 and mitotic index on hormone receptor-positive, HER2-negative breast carcinoma.
abstract: BACKGROUND
  Inconsistencies between mitotic index (MI) and Ki67 measures have been identified in many breast tumour samples. The aim of this study was to describe the prognosis of hormone receptor-positive (HR+) HER2- tumours having discrepant MI and Ki67.
  
  
  METHODS
  We included a cohort of breast cancer patients initially treated by surgery between 2001 and 2005 in the Institut Curie. Breast cancer-specific survival (BCSS) and disease-free survival (DFS) were analysed according to three proliferation groups: high MI/high Ki67 (MI=3, Ki67>20%), low MI/low Ki67 (MI<3, Ki67⩽20%) and discrepant (high MI/low Ki67 or low MI/high Ki67).
  
  
  RESULTS
  Among the 1430 patients, 19.6% had discrepant Ki67 and MI, 11.6% had high markers and 68.8% had low markers. The 5-year BCSS was 95.8%, 95% CI (0.93-0.98) in the discrepant group, 99.3%, 95% CI (0.993-0.999) in the low-proliferation group and 91.8%, 95% CI (0.88-0.96) in the high-proliferation group. In multivariate analysis, the survival of the discrepant group was lower than that of the low-proliferation group: BCSS hazard ratio (HR)=3.01 (1.32-6.84; P=0.008) and DFS HR=2.07, 95% CI (1.31-3.26; P=0.002). Among grade 2 tumours in multivariate analysis, DFS of the discrepant group was lower than that of the low MI/low Ki67 group: HR=1.98, 95% CI (1.14-3.46), P=0.02. Regarding BCSS, the obtained results were similar.
  
  
  CONCLUSIONS
  The prognosis of patients with discrepant MI and Ki67 appears intermediate between that of low MI/low Ki67 and high MI/high Ki67 groups. These markers should be jointly analysed to clarify prognosis.
authors.affiliation: Département de chirurgie, Institut Curie, 75005 Paris, France.
authors.forename: L
authors.initials: L
authors.lastname: Rossi
authors.affiliation: Service de Gynécologie-Obstétrique, Hôpital Tenon, 75020 Paris, France.
authors.forename: E
authors.initials: E
authors.lastname: Laas
authors.affiliation: Craigavon Area Hospital Breast Unit BT63 5QQ, Portadown, Northern Ireland.
authors.forename: P
authors.initials: P
authors.lastname: Mallon
authors.affiliation: Département de biologie des tumeurs, Institut Curie, 75005 Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Vincent-Salomon
authors.affiliation: Département de biologie des tumeurs, Institut Curie, 75005 Paris, France.
authors.forename: J-M
authors.initials: JM
authors.lastname: Guinebretiere
authors.affiliation: Département d'oncologie médicale, Institut Curie, 75005 Paris, France.
authors.forename: F
authors.initials: F
authors.lastname: Lerebours
authors.affiliation: Département de chirurgie, Institut Curie, 75005 Paris, France.|Equipe d'Accueil 7285, 'Risk and Safety in Clinical Medicine for women and Perinatal Health', University Versailles-Saint-Quentin, 78180 Montigny-le-Bretonneux, France.
authors.forename: R
authors.initials: R
authors.lastname: Rouzier
authors.affiliation: Département d'oncologie médicale, Institut Curie, 75005 Paris, France.
authors.forename: J-Y
authors.initials: JY
authors.lastname: Pierga
authors.affiliation: Département de chirurgie, Institut Curie, 75005 Paris, France.|Département de recherche translationnelle, Equipe résidu tumoral et réponse au traitement, Institut Curie, 75005 Paris, France.|INSERM U932 Immunity and Cancer, Institut Curie, 75005 Paris, France.
authors.forename: F
authors.initials: F
authors.lastname: Reyal
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis*; D008940:Mitotic Index; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011987:Receptors, Steroid / Q000378:metabolism; D016019:Survival Analysis
chemical_list: D019394:Ki-67 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D011987:Receptors, Steroid; C508053:ERBB2 protein, human