Immunohistochemical Characterization of a Squamous Cell Carcinoma in a Harbour Porpoise (Phocoena phocoena) from German Waters

SummaryNeoplastic diseases in cetaceans are considered relatively uncommon. This report describes a gastric squamous cell carcinoma in an adult male harbour porpoise (Phocoena phocoena) stranded on the North Sea coast of Schleswig–Holstein, Germany. The tumour arose from the squamous epithelium of the first compartment of the stomach and metastases were found in the pulmonary and retropharyngeal lymph nodes, liver, lung and brain. Neoplastic epithelial cells expressed cytokeratin (CK) 5, CK6 and CK10. This pattern of CK expression did not differ from that of normal porpoise squamous gastric mucosa and partially shares the CK profile of human oesophageal epithelium. Tumour cells strongly expressed p53, suggesting a possible role for this tumour suppressor gene in tumourigenesis.