title: The importance of tissue handling of surgically removed breast cancer for an accurate assessment of the Ki-67 index.
abstract: OBJECTIVE
  Insufficient attention for the Ki-67 immunohistochemistry has been given to the importance of tissue handling for surgical breast cancer specimens. We sought to investigate the effect of fixation status on the Ki-67.
  
  
  METHODS
  We examined the effect of fixative, time to and duration of fixation using surgical specimens, and finally, compared the paired Ki-67 index in the tumour between core needle and surgical specimen.
  
  
  RESULTS
  The Ki-67 was significantly higher when 10% neutral buffered formalin was used (p=0.0276). Insufficient fixation caused a drastic reduction in the Ki-67 index (p=0.0177), but not significant in oestrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2). Sixteen hours delayed time to fixation also caused a reduction of the Ki-67 (p=0.0284), but not significant in ER. Prolonged fixation significantly led to a gradual reduction in the Ki-67 in a time-dependent manner, but not in both ER and HER2. Finally, cutting the tumour before fixation improved fixation status and consequently caused an increased level of the Ki-67 index (p=0.0181), which resulted in a strong correlation of the Ki-67 between core needle and surgical specimen (r=0.8595).
  
  
  CONCLUSIONS
  Tissue handling of surgical specimen is critical for assessing the Ki-67 compared with ER and HER2. We should pay more attention to tissue fixation status for the standard assessment of the Ki-67 index.
authors.affiliation: Department of Pathology, Kumamoto Shinto General Hospital, Kumamoto, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Arima
authors.affiliation: Department of Breast Oncology, Kumamoto Shinto General Hospital, Kumamoto, Japan.
authors.forename: Reiki
authors.initials: R
authors.lastname: Nishimura
authors.affiliation: Department of Breast Oncology, Kumamoto Shinto General Hospital, Kumamoto, Japan.
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Osako
authors.affiliation: Department of Breast Oncology, Kumamoto Shinto General Hospital, Kumamoto, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Nishiyama
authors.affiliation: Department of Breast Oncology, Kumamoto Shinto General Hospital, Kumamoto, Japan.
authors.forename: Mamiko
authors.initials: M
authors.lastname: Fujisue
authors.affiliation: Department of Breast & Endocrine Surgery, Kumamoto City Hospital, Kumamoto, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Okumura
authors.affiliation: Department of Breast & Endocrine Surgery, Kumamoto City Hospital, Kumamoto, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakano
authors.affiliation: Department of Surgery, Kumamoto City Hospital, Kumamoto, Japan.
authors.forename: Rumiko
authors.initials: R
authors.lastname: Tashima
authors.affiliation: Department of Pathology, Kumamoto City Hospital, Kumamoto, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Toyozumi
mesh_terms: D062005:Biopsy, Large-Core Needle; D001943:Breast Neoplasms / Q000737:chemistry* / Q000473:pathology / Q000601:surgery*; D005260:Female; D005404:Fixatives; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis*; D008408:Mastectomy; D011237:Predictive Value of Tests; D055550:Protein Stability; D059748:Proteolysis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D015203:Reproducibility of Results; D013048:Specimen Handling / Q000379:methods*; D013997:Time Factors; D016707:Tissue Fixation / Q000379:methods*
chemical_list: D005404:Fixatives; D019394:Ki-67 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; C508053:ERBB2 protein, human
keywords: BREAST CANCER; IMMUNOHISTOCHEMISTRY; PROLIFERATION; TUMOUR BIOLOGY