Tp53 expressing squamous cell carcinoma of the tonsil in a captive polar wolf (Canis lupus arctos).

The gross and histopathologic findings for a primary tonsillar squamous cell carcinoma in a captive 11-yr-old male polar wolf (Canis lupus arctos) are described. The carcinoma had metastasized to regional lymph nodes of the pharynx, the precardial mediastinum, and the lungs. Tumor suppressor protein TP53 was detected by immunohistochemistry in the nuclei of poorly differentiated, cytokeratin-positive cells of the primary neoplasm and the metastases. Canine oral papillomavirus DNA was not detectable by polymerase chain reaction (PCR).