Immunohistochemical expression of proliferation markers in canine osteosarcoma

Abstract

Canine osteosarcoma is an extremely malignant bone tumor that often arises in the bones of the limbs. It is a highly metastatic disease distinguished by proliferative bone lesions and a tendency for pulmonary metastasis. Overexpression of proliferative proteins are associated with bad prognosis in human osteosarcoma. Here, we tested the expression of the different proliferative proteins (p53, p16, vimentin, and mdm2) in nine archival samples with canine osteosarcoma. Paraffin-embedded tissue sections were confirmed by histopathology and stained by immunohistochemistry for p53, p16, vimentin and mdm2. Positive expression of these proteins was evaluated as the ratio of positive cancer cells and the intensity staining was assessed in several areas. Histopathologically, 95% of samples were grade II and III. All high-grade osteosarcomas were particularly cellular. The cancer cells were generally large spindle-shaped and large nucleus with distribution of osteoid between the cancer cells. Immunohistochemical detection of p53, p16, vimentin and mdm2 was 89%, 56%, 78%, and 89% of samples respectively. The staining intensity for p53, p16, vimentin and mdm2 was particularly nuclear in 81%, 66%, 78%, and 79% of the cancer cells respectively. Our present work suggests that p53, p16, vimentin, and mdm2 were detected in grade III canine osteosarcomas samples. In addition, these proliferative markers are the significant biomarkers in canine osteosarcomas and can be used as a predictor for diagnostic and prognostic value and allowing cancer differentiation. This primary data supports that both canine and human osteosarcomas share same molecular characters which are approved by expression of proliferative genes.