title: Association of Ki67 index with prognosis for intermediate-grade canine cutaneous mast cell tumours.
abstract: Intermediate-grade mast cell tumours (MCT) represent a heterogeneous population of tumours. The prognosis for the majority of dogs is excellent following surgical excision, but a minority die because of their disease. A previous study identified Ki67 expression as a predictor of prognosis in all three grades of MCT. The purpose of this study was to validate those results in a new group of dogs, with intermediate-grade MCT only. Ki67 immunohistochemistry was performed on intermediate-grade MCT from 163 dogs with known outcome. Digital microscopy images were taken from each tumour, and an index calculated of Ki67-positive cells. Ki67 index as a binary variable with a cut-off value of 1.8% was confirmed to be associated with prognosis (hazard ratio = 19.1, P < 0.0001) for this cohort of dogs. The 1-year, 2-year and 3-year survival probabilities (with standard errors) of 127 dogs with a Ki67 index <or=1.8% were [0.95 (0.024), similar for all] and for 36 dogs with a Ki67 index >1.8% were 0.54 (0.100), 0.45 (0.101) and 0.33 (0.104), respectively.
authors.affiliation: Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, UK.
authors.forename: G A
authors.initials: GA
authors.lastname: Maglennon
authors.forename: S
authors.initials: S
authors.lastname: Murphy
authors.forename: V
authors.initials: V
authors.lastname: Adams
authors.forename: J
authors.initials: J
authors.lastname: Miller
authors.forename: K
authors.initials: K
authors.lastname: Smith
authors.forename: A
authors.initials: A
authors.lastname: Blunden
authors.forename: T J
authors.initials: TJ
authors.lastname: Scase
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000097:blood*; D004285:Dogs; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D019394:Ki-67 Antigen / Q000097:blood*; D008297:Male; D034701:Mastocytosis, Cutaneous / Q000097:blood / Q000662:veterinary*; D009367:Neoplasm Staging / Q000662:veterinary; D011379:Prognosis; D012189:Retrospective Studies
chemical_list: D019394:Ki-67 Antigen