title: Automated quantification of proliferation with automated hot-spot selection in phosphohistone H3/MART1 dual-stained stage I/II melanoma.
abstract: BACKGROUND
  Staging of melanoma includes quantification of a proliferation index, i.e., presumed melanocytic mitoses of H&E stains are counted manually in hot spots. Yet, its reproducibility and prognostic impact increases by immunohistochemical dual staining for phosphohistone H3 (PHH3) and MART1, which also may enable fully automated quantification by image analysis. To ensure manageable workloads and repeatable measurements in modern pathology, the study aimed to present an automated quantification of proliferation with automated hot-spot selection in PHH3/MART1-stained melanomas.
  
  
  METHODS
  Formalin-fixed, paraffin-embedded tissue from 153 consecutive stage I/II melanoma patients was immunohistochemically dual-stained for PHH3 and MART1. Whole slide images were captured, and the number of PHH3/MART1-positive cells was manually and automatically counted in the global tumor area and in a manually and automatically selected hot spot, i.e., a fixed 1-mm(2) square. Bland-Altman plots and hypothesis tests compared manual and automated procedures, and the Cox proportional hazards model established their prognostic impact.
  
  
  RESULTS
  The mean difference between manual and automated global counts was 2.9 cells/mm(2) (P = 0.0071) and 0.23 cells per hot spot (P = 0.96) for automated counts in manually and automatically selected hot spots. In 77 % of cases, manual and automated hot spots overlapped. Fully manual hot-spot counts yielded the highest prognostic performance with an adjusted hazard ratio of 5.5 (95 % CI, 1.3-24, P = 0.024) as opposed to 1.3 (95 % CI, 0.61-2.9, P = 0.47) for automated counts with automated hot spots.
  
  
  CONCLUSIONS
  The automated index and automated hot-spot selection were highly correlated to their manual counterpart, but altogether their prognostic impact was noticeably reduced. Because correct recognition of only one PHH3/MART1-positive cell seems important, extremely high sensitivity and specificity of the algorithm is required for prognostic purposes. Thus, automated analysis may still aid and improve the pathologists' detection of mitoses in melanoma and possibly other malignancies.
authors.affiliation: Department of Pathology, Aarhus University Hospital, Nørrebrogade 44, DK-8000, Aarhus C, Denmark. swittenp@gmail.com.
authors.forename: Patricia Switten
authors.initials: PS
authors.lastname: Nielsen
authors.affiliation: Department of Pathology, Aarhus University Hospital, Nørrebrogade 44, DK-8000, Aarhus C, Denmark.
authors.forename: Rikke
authors.initials: R
authors.lastname: Riber-Hansen
authors.affiliation: Department of Oncology, Aarhus University Hospital, Nørrebrogade 44, DK-8000, Aarhus C, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Schmidt
authors.affiliation: Department of Pathology, Aarhus University Hospital, Nørrebrogade 44, DK-8000, Aarhus C, Denmark.
authors.forename: Torben
authors.initials: T
authors.lastname: Steiniche
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D057205:Automation, Laboratory; D014408:Biomarkers, Tumor / Q000032:analysis*; D049109:Cell Proliferation; D003718:Denmark; D005260:Female; D006657:Histones / Q000032:analysis*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D058965:MART-1 Antigen / Q000032:analysis*; D008297:Male; D008545:Melanoma / Q000737:chemistry* / Q000473:pathology; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D010766:Phosphorylation; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D015203:Reproducibility of Results; D012878:Skin Neoplasms / Q000737:chemistry* / Q000473:pathology; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D006657:Histones; D058965:MART-1 Antigen; C548667:MLANA protein, human
keywords: Computer-assisted image analysis; Hot spot; Immunohistochemical double staining; Melanoma; Phosphohistone H3; Prognosis; Proliferation index