Phosphatidylinositol-3-kinase-AKT pathway, phospho-JUN and phospho-JNK expression in spontaneously arising bovine urinary bladder tumours

The aetiopathogenesis of urinary bladder tumours in cattle involves prolonged ingestion of bracken fern and infection by bovine papillomavirus types 1 or 2 (BPV-1/2). E5, the major BPV-1/2 oncoprotein, binds to the activated platelet-derived growth factor beta receptor (pPDGF-betaR), inducing cell transformation in vitro and spontaneously arising urinary bladder tumours. The aim of this study was to assess whether the 85 kDa regulatory subunit (p85) of the phosphatidylinositol-3-kinase (PI3K)-AKT pathway and other transforming signals phospho-JUN (pJUN) and phospho-JUN N-terminal kinases (pJNK) may be important in the development of BPV-associated urothelial carcinomas. A physical interaction between the pPDGF-betaR and PI3K was shown in four tumours and two samples of normal bladder tissue by co-immunoprecipitation and western blotting. There was greater expression of the PI3K-AKT-cyclin D3 molecular pathway downstream to the activation of pPDGF-betaR in neoplastic compared with normal tissue. pJNK and pJUN were overexpressed in samples of tumour compared with normal mucosal tissue. These findings provide new insights into the aetiopathogenic mechanisms underlying naturally occurring bovine urothelial carcinogenesis and contribute to understanding of the role of E5 oncoprotein in naturally occurring tumorigenesis.

Sigma-2 receptor expression in bovine papillomavirus-associated urinary bladder tumours

The expression of sigma-2 receptors was investigated in nine urothelial tumours of the urinary bladder of cattle. Each tumour was associated with the presence of DNA of bovine papillomavirus type-2 (BPV-2) and expression of the E5 viral oncoprotein. Five tumours were classified as low-grade carcinoma on the basis of morphological criteria and calculation of mean nuclear area (MNA) and mean nuclear perimeter (MNP). Four tumours were classified as high-grade carcinoma. Sigma-2 receptors were overexpressed in both types of carcinoma. In control normal bovine bladder tissue the density of receptors (expressed as the B(max)) was 0.37 pmol/mg of protein. Low-grade carcinomas had a mean B(max) of 1.37+/-0.32 pmol/mg of protein (range 1.03-1.86) and in high-grade carcinomas the mean B(max) was 10.9+/-2.8 pmol/mg of protein (range 8.2-14). The difference in B(max) between low- and high-grade carcinomas was statistically significant (P=0.0001).

Lymphoepithelioma-like carcinoma of the urinary bladder in a cow associated with bovine papillomavirus type-2

Lymphoepithelioma-like carcinoma (LELCA) of the urinary bladder is reported in a 7-year-old cow that had grazed pasture rich in bracken fern and had suffered from severe intermittent haematuria from 3 to 4 years of age. On necropsy examination there were multiple haemorrhagic foci scattered over the mucosal surface of the urinary bladder. Microscopically there were nests, cords and sheets of neoplastic cells infiltrating the lamina propria and muscularis propria. These had a syncytial appearance with ill-defined cytoplasmic borders, large nuclei and prominent nucleoli. There was a prominent associated inflammatory infiltrate comprising lymphocytes and plasma cells with sparse histiocytes and granulocytes. Immunohistochemically, LELCA cells expressed cytokeratin but not vimentin. The LELCA was focally admixed with a concomitant papillary high-grade carcinoma that also infiltrated the lamina propria. A diffuse carcinoma in situ was also present. Bovine papillomavirus type-2 (BPV-2) DNA was amplified from frozen neoplastic tissue and from selected areas of formalin-fixed, paraffin wax-embedded tissue obtained by laser capture microdissection. Microbiological culture of a urine sample resulted in isolation of Weeksella virosa, Rhizobium radiobacter and Staphylococcus warneri. Flow cytometric analysis performed on blood mononuclear cells revealed down-regulation of a panel of markers including CD3, CD4, CD8alpha, CD45, MHC class I and MHC class II (HLA-DRalpha, HLA-DQ, HLA-DP). This report extends the spectrum of neoplastic urothelial lesions described in cattle and provides further evidence that some features of these tumours are similar to human counterparts.

Melanosis of the Urinary Bladder in a Cow

Melanosis of the urinary bladder is a very rare condition characterized by an abnormal black or brownish-black pigmentation of the organ. The pigmentary disorder can involve both the urothelial cell layers and/or the submucosa. The biologic potential of the melanosis of urinary bladder remains unknown because only a few cases have been reported in medical literature. So far melanosis of the urinary bladder is not known to occur in cattle. Here we describe the first case of melanosis of the urinary bladder in an inbred red-spotted, 7-year-old cow. Light, ultrastructural, and immunohistochemic investigations demonstrated melanin pigment in the submucosa and lamina propria but not the urothelium of the bladder. In addition, biochemical characterization of the pigment-laden cells demonstrated that the pigment of this disorder consisted mainly of eumelanin, thus corroborating the morphologic studies. Finally, virologic examination revealed the presence of bovine papillomavirus type 2.

Multiple Glomus Tumors of the Urinary Bladder in a Cow Associated with Bovine Papillomavirus Type 2 (BPV-2) Infection

We report a case of multiple glomus tumors associated with bovine papillomavirus type 2 (BPV-2) infection in the urinary bladder of a 13-year-old cow suffering from severe chronic enzootic hematuria. Macroscopically, multiple submucosal reddish nodules were seen swelling the vesical mucosa. Histologically, neoplastic proliferation was characterized by the presence of numerous blood vessels. These were lined by normal endothelial cells surrounded by round epithelioid cells with central nuclei, prominent nucleoli, acidophilic cytoplasm, and well-defined cytoplasmic borders. Tumor cells were distributed around open vascular lumina and in perivascular spaces. They were immunohistochemically positive for actin and vimentin and negative for cytokeratins, desmin, and factor VIII-related antigen. On the basis of these findings, this tumor was diagnosed as glomus tumor, a neoplasm not previously reported in cattle and exceedingly rare in animals. BPV-2 DNA was amplified from the formalin-fixed, paraffin-processed tissue specimens obtained by laser capture microdissection. This report widens the spectrum of mesenchymal tumors of the bovine urinary bladder. Finally, the microscopic pattern of tumor described here shares striking morphologic and immunohistochemical similarities with the angiomatous form of glomus tumor known to occur in man.