Comparative study on the expression pattern of the proliferating cell markers PCNA and Ki67 in canine mammary tumours Ranganath G.J.*,4, Kumar Ram4, Reddy A.P. Vishwanatha1,4, Mayilkumar . K.4, Pawaiya R.V.S2,4, Maiti S.K.3,4 4Division of Pathology, Indian Veterinary Research Institute, Izatnagar, Bareilly, U.P 1Division of Biochemistry, Indian Veterinary Research Institute, Izatnagar, Bareilly, U.P 3Division of Surgery, Indian Veterinary Research Institute, Izatnagar, Bareilly, U.P 2CIRG, Makhdoom, Mathura, UP *Corresponding author; e-mail: drranganathgjvet@gmail.com
Abstract In the present study, we analyzed the pattern of expression of proliferating cell markers PCNA and Ki67 semi-quantitatively by immunohistochemistry in different histological subtypes of canine mammary tumours. Immunostaining was performed by employing PC10 and PP67 monoclonal antihuman antibodies against PCNA and Ki67 respectively. Out of 103 canine mammary tumours 98 were diagnosed as malignant and only 5 diagnosed as benign tumours. Reactivity to PCNA and Ki67 localized to nuclei in non-mitotic cells; but in mitotic cells PCNA immunostaining was cytoplasmic and Ki-67 expression was chromosomal. Proliferation indices determined were generally higher for PCNA compared to Ki67. Intensity and distribution of staining was more in the basal layer of tubular and tubulopapillary carcinomas and adenomas however, in benign and malignant mixed tumours the intensity and numbers of positive cells were more just around the myoepithelial cell nests and cartilaginous or bony metaplasia. PCNA and Ki67 indices were significantly higher in malignant tumours compared to benign counterparts (P<0.05). Among malignant tumours PCNA and Ki67 indices were significantly higher in osteosarcomas, carcinosarcomas and solid carcinomas compared to complex carcinomas, tubular carcinoma, tubulopapillary carcinoma, malignant mixed tumours, and fibrosarcomas (P<3.05), however, there was no significant difference was found between later 5 types. Further PCNA and Ki67 indices were positively correlated with each other in both benign and malignant tumours (P <3.01). In conclusion, high PCNA and Ki67 indices were associated with malignancy and poorly differentiated tumours. Top Keywords Immunohistochemistry, Ki67, Mammary tumours, PCNA. Top |