Cytological, Histological, Ultrastructural, Molecular And Immunohistochemical Studies On Canine Mammary Tumours
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Date
2004
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Publisher
Tamil Nadu Veterinary and Animal Sciences University
Abstract
The present study was undertaken to assess different classification system of canine mammary
tumours in order to analyse the diagnostic and prognostic outcome of the mammary tumours in
dogs. Sixty clinical cases of mammary tumours were studied during the period from April 2002 to
April 2004. Specimens collected were from bitches. The mean age incidence was 8.63 years.
Spitz showed highest incidence of mammary tumours.
A total of 85 tumours were recorded, of which 82 were malignant and 3 were benign. Forty four
tumours were seen in the right chain while 41 were seen on the left chain. Most of the tumours
were located in the posterior glands (89.41 per cent). Metastasis was seen in the lungs and lymph
nodes. Mortality was maximum in the recurrent (47.06 per cent) than non-recurrent (27.91 per
cent) cases.
Based upon the WHO's International Classification, malignant tumours like tubular
adenocarcinoma (simple, n=9 and complex, n=23), papillary adenocarcinoma (simple, n=2 and
complex, n=2), papillary cystic adenocarcinoma (complex type, n=2), solid carcinoma (simple, n=1
and complex, n=10), spindle cell carcinoma (n=3), anaplastic carcinoma, squamous cell carcinoma
(simple, n=2 and complex, n=8), osteosarcoma (n=1), fibrosarcoma (n=1) and carcinosarcoma
(n=10) and benign tumours like adenoma (n=1), fibroadenoma (n=1) and benign mixed tumour
(n=1) were recorded. Survivability was grave with solid carcinoma, anaplastic carcinoma andfibrosarcoma. Cytologically, malignant mammary tumours were clearly differentiated from benign
varieties.
Biochemically, enhanced lipid peroxidation with increased SOD, CAT, GSH, GPx and GST
observed indicated free radical induced DNA injury providing selective growth advantage to
tumour cells over normal counter parts. Leukocytosis with neutrophilia and lymphocytosis and mild
anaemia were recorded in all cases. AgNOR ratio, number and content analysis showed sarcoma
were more malignant than carcinomas. TNM's clinical stages II and IV had grave prognosis where
more recurrence and deaths were recorded. Grade III tumours of TNM's histological grading had
poor prognosis. Survivability reduced with increase in mitotic index.
p 53 immunoreactivity indicated molecular p 53 tumour suppressor gene mutation. Ulcerated
tumours with p 53 mutation had least survival than ulcerated tumours without p 53 mutation.
Immunostaining of PCNA may or may not be useful as a prognostic factor. Reduced survivability
was observed in tumour bearing groups having high PCNA and caspase-3 activities. Survivability
was good in animals with higher ER-α immunoreactivity. Pathological changes at molecular levels
could be clearly appreciated by electronmicroscopy. The entire open reading frame of p 53 gene
(1178bp) was amplified using RT-PCR to analyse mutation in the gene.
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Keywords
Canine mammary tumour, Antioxidants, Immunohistochemistry, p53, PCNA, Caspase-3, ER-α, p53 gene, Pathomorphology, Ultrastructure