title: Validity and reproducibility of Ki-67 assessment in gastrointestinal stromal tumors and leiomyosarcomas.
abstract: With the aim of standardizing Ki-67 immunohistochemistry, we assessed interobserver and interlaboratory variability of the Ki-67 labeling index and Ki-67 score among eight general pathologists for 24 gastrointestinal stromal tumors (GISTs) and 12 leiomyosarcomas, which were predominantly of the gastrointestinal (GI) tract, mesentery and retroperitoneum, based on a review of a tissue microarrays subjected to immunohistochemistry with antibodies for Ki-67. For Ki-67 immunostaining of mesenchymal tumors of the GI tract, including GISTs, differences were seen in the scores given by regional hospitals. Conversely, for two categories of the Ki-67 labeling index, namely <10% and ≥10%, concordance of the Ki-67 score between microscopic observation and image analysis, and between the observers, was good, but it was not good for the other four categories of the index for <5%, 5-9%, 10-29%, and ≥30%. The concordance of the Ki-67 scores between the observers in two categories was higher using the Ki-67 pre-stained tissue microarrays (TMAs) within each participating institute than that using the Ki-67 stained TMAs between the participating institutes. The reproducibility of a 10% cut-off value for the Ki-67 labeling index to predict the prognosis of GISTs was relatively high, but there is an urgent need to standardize the staining technique.
authors: Department of Surgical Pathology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Jiro
authors: J
authors: Ogino
authors: Hiroko
authors: H
authors: Asanuma
authors: Yutaka
authors: Y
authors: Hatanaka
authors: Yoshihiro
authors: Y
authors: Matsuno
authors: Hiroko
authors: H
authors: Gotoda
authors: Shunji
authors: S
authors: Muraoka
authors: Takayuki
authors: T
authors: Tsuji
authors: Yuichiro
authors: Y
authors: Fukazawa
authors: Katsushige
authors: K
authors: Yamashiro
authors: Nobuo
authors: N
authors: Kondo
authors: Hiroyuki
authors: H
authors: Iwaki
authors: Naoyuki
authors: N
authors: Miyokawa
authors: Tadashi
authors: T
authors: Hasegawa
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D005770:Gastrointestinal Neoplasms / Q000473:pathology*; D046152:Gastrointestinal Stromal Tumors / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis*; D007890:Leiomyosarcoma / Q000473:pathology*; D060787:Neoplasm Grading / Q000379:methods / Q000592:standards*; D011379:Prognosis; D015203:Reproducibility of Results; D012983:Soft Tissue Neoplasms / Q000473:pathology*; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen