Association of Ki67 index with prognosis for intermediate-grade canine cutaneous mast cell tumours.
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.
Maglennon
G A
GA
Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, UK.
Murphy
S
S
Adams
V
V
Miller
J
J
Smith
K
K
Blunden
A
A
Scase
T J
TJ
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
D019394:Ki-67 Antigen