Association of Ki67 index with prognosis for intermediate‐grade canine cutaneous mast cell tumours* |
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| Authors: | G A Maglennon S Murphy V Adams J Miller K Smith A Blunden T J Scase |
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| Institution: | 1. Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, UK;2. Present address: Division of Virology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.;3. Present address: Department of Pathology and Infectious Disease, Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA, UK;4. Present address: Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK |
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| 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 ≤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. |
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| Keywords: | canine Ki67 mast cell tumour prognosis |
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