title: Quantitative tumor heterogeneity assessment on a nuclear population basis.
abstract: Immunohistochemistry Ki-67 stain is widely used for visualizing cell proliferation. The common method for scoring the proliferation is to manually select and score a hot spot. This method is time-consuming and will often not give reproducible results due to subjective selection of the hotspots and subjective scoring. An automatic hotspot detection and proliferative index scoring would be time-saving, make the determination of the Ki-67 score easier and minimize the uncertainty of the score by introducing a more objective and standardized score. Tissue Micro Array cores stained for Ki-67 and their neighbor slide stained for Pan Cytokeratin were aligned and Ki-67 positive and negative nuclei were identified inside tumor regions. A heatmap was calculated based on these and illustrates the distribution of the heterogenous response of Ki-67 positive nuclei in the tumor tissue. An automatic hot spot detection was developed and the Ki-67 score was calculated. All scores were compared with scores provided by a pathologist using linear regression models. No significant difference was found between the Ki-67 scores guided by the developed heatmap and the scores provided by a pathologist. For comparison, scores were also calculated at a random place outside the hot spot and these scores were found to be significantly different from the pathologist scores. A heatmap visualizing the heterogeneity in tumor tissue expressed by Ki-67 was developed and used for an automatic identification of hot spots in which a Ki-67 score was calculated. The Ki-67 scores did not differ significantly from scores provided by a pathologist. © 2017 International Society for Advancement of Cytometry.
authors.affiliation: DTU Compute, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
authors.forename: Anne-Sofie
authors.initials: AS
authors.lastname: Wessel Lindberg
authors.affiliation: DTU Compute, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
authors.forename: Knut
authors.initials: K
authors.lastname: Conradsen
authors.affiliation: DTU Compute, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
authors.forename: Rasmus
authors.initials: R
authors.lastname: Larsen
authors.affiliation: Visiopharm, DK-2970, Hoersholm, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Friis Lippert
authors.affiliation: Institute of Pathology, Aalborg University Hospital, DK-9100, Aalborg, Denmark.
authors.forename: Rasmus
authors.initials: R
authors.lastname: Røge
authors.affiliation: Institute of Pathology, Aalborg University Hospital, DK-9100, Aalborg, Denmark.
authors.forename: Mogens
authors.initials: M
authors.lastname: Vyberg
mesh_terms: D000465:Algorithms; D014408:Biomarkers, Tumor / Q000235:genetics*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000648:ultrastructure; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure*; D049109:Cell Proliferation; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007150:Immunohistochemistry / Q000592:standards; D007633:Keratins / Q000235:genetics*; D019394:Ki-67 Antigen / Q000235:genetics*; D016014:Linear Models; D015203:Reproducibility of Results; D046888:Tissue Array Analysis / Q000592:standards
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D007633:Keratins
keywords: Ki-67 antigen; breast cancer; computer-assisted image analysis; heatmap; heterogeneity; hot spot; hot spot detection