HSP32 and HSP90 Immunoexpression, in Relation to Kit Pattern, Grading, and Mitotic Count in Canine Cutaneous Mast Cell Tumors.

Literature data indicate heat shock protein (Hsp) 32 and 90 as potential molecular targets in canine neoplastic mast cells (MCs). However, their immunoexpression patterns in canine mast cell tumors (MCTs) have not been investigated. Thus, the aim of this study was to evaluate the immunohistochemical expression of Hsp32 and Hsp90 in 22 canine cutaneous MCTs, in relation to KIT immunolabeling pattern, histological grade, and mitotic count. All cases showed cytoplasmic labeling of Hsp90, variably associated with nuclear and/or membranous labeling. Relationships of Hsp90 or Hsp32 immunolabeling with KIT pattern, mitotic count, and tumor grade were not observed. However, the reduced Hsp32 immunoexpression observed in most grade III/high-grade MCTs suggests a tendency toward a loss of immunosignal in poorly differentiated MCs. The great heterogeneity in extent and distribution of Hsp90 immunoexpression among the different MCT cases may also partially explain the difficulties in predicting the in vivo biologic activity of Hsp90 inhibitors on canine MCTs.

17-AAG and Apoptosis, Autophagy, and Mitophagy in Canine Osteosarcoma Cell Lines.

Canine osteosarcoma is highly resistant to current chemotherapy; thus, clarifying the mechanisms of tumor cell resistance to treatments is an urgent need. We tested the geldanamycin derivative 17-AAG (17-allylamino-17-demethoxygeldanamycin) prototype of Hsp90 (heat shock protein 90) inhibitors in 2 canine osteosarcoma cell lines, D22 and D17, derived from primary and metastatic tumors, respectively. With the aim to understand the interplay between cell death, autophagy, and mitophagy, in light of the dual effect of autophagy in regulating cancer cell viability and death, D22 and D17 cells were treated with different concentrations of 17-AAG (0.5 µM, 1 µM) for 24 and 48 hours. 17-AAG-induced apoptosis, necrosis, autophagy, and mitophagy were assessed by transmission electron microscopy, flow cytometry, and immunofluorescence. A simultaneous increase in apoptosis, autophagy, and mitophagy was observed only in the D22 cell line, while D17 cells showed low levels of apoptotic cell death. These results reveal differential cell response to drug-induced stress depending on tumor cell type. Therefore, pharmacological treatments based on proapoptotic chemotherapy in association with autophagy regulators would benefit from a predictive in vitro screening of the target cell type.

Survivin and related proteins in canine mammary tumors: immunohistochemical expression.

Survivin is reexpressed in most human breast cancers, where its expression has been associated with tumor aggressiveness, poor prognosis, and poor response to therapy. Survivin expression was evaluated in 41 malignant canine mammary tumors (CMTs) by immunohistochemistry, in relation to histological grade and stage, and correlated with that of some related molecules (ß-catenin, caspase 3, heat shock proteins) to understand their possible role in canine mammary tumorigenesis. An increase in nuclear survivin expression, compared with healthy mammary glands, was observed in CMTs, where nuclear immunolabeling was related to the presence of necrosis. No statistically significant relation was found between the expression of the investigated molecules and the histological grade or stage. The present study may suggest an important involvement of survivin in CMT tumorigenesis. Its overexpression in most of the cases evaluated might suggest that targeting survivin in CMTs may be a valid anticancer therapy.

Diffuse Pulmonary Adenocarcinoma with Micropapillary Growth Pattern in a Cat.

A 12-year-old female European shorthair cat was presented with severe dyspnoea. Echocardiography revealed hypertrophic cardiomyopathy and pleural effusion. The cat died from acute decompensated left heart failure. At necropsy examination, the lungs were diffusely congested and firm, with multifocal grey areas and sparse haemorrhages. No solid masses were detected. Histopathology revealed a diffuse neoplastic proliferation characterized by irregular growth along alveolar walls with a micropapillary pattern. Tumour cells were large, highly pleomorphic and intensely positive for pan-cytokeratin and CAM 5.2. Tumour growth was obscured by simultaneous lesions related to chronic pulmonary congestion and interstitial lung disease. Histological features were consistent with a diffuse invasive pulmonary adenocarcinoma with a micropapillary pattern of tumour growth. Differential diagnosis included large cell carcinoma, which is usually characterized by rosettes or solid clusters of cells occupying alveolar lumen. Extensive cytokeratin immunolabelling was helpful in the differentiation from histiocytic proliferative disease.

Unexpected Cardiac Death During Anaesthesia of a Young Rabbit Associated with Fibro-fatty Replacement of the Right Ventricular Myocardium.

A 6-month-old female pet rabbit was presented for routine ovariectomy. The pre-anaesthetic evaluation was unremarkable and no anaesthetic complications occurred during the procedure. However, at the end of the surgery, the rabbit suddenly showed acute bradycardia and cardiac death. Necropsy examination revealed marked dilation of the right ventricle, associated with diffuse thinning of the right ventricular free wall. Gross and histopathological findings were suggestive of a congenital dilated cardiomyopathy characterized by fibro-fatty replacement of the right ventricular myocardium. Similar myocardial lesions have not been previously described in rabbits, although they have been documented in myocardial diseases of man, dogs, cats, cattle, horses and chimpanzees.

Immunohistochemical expression of heat shock proteins, p63 and androgen receptor in benign prostatic hyperplasia and prostatic carcinoma in the dog.

This study compared heat shock proteins Hsp60, Hsp72 and Hsp73, along with p63 and androgen receptor (AR) immunoexpression between 16 cases of benign prostatic hyperplasia (BPH) and 11 prostatic carcinomas (PCa) in dogs. The proportion of Hsp60-positive cells was higher in PCa compared with BPH (P = 0.033), whereas the frequency and intensity of Hsp73 immunostaining did not differ significantly between the two groups. Hsp72-immunostained nuclei formed a discontinuous layer along the basement membrane in BPH, whereas cells in this layer in PCa were negative or weakly positive. Hsp72 nuclear score showed significant positive associations with both p63 (P = 0.016) and AR (P = 0.009) scores. Double immunofluorescence revealed Hsp72-p63 and Hsp72-AR co-expressions in basal cell nuclei. Aberrant cytoplasmic p63 immunolabelling was observed in 3 of 11 PCa cases. These results suggest a role of the combined expression of Hsp72, p63 and AR in basal epithelial cells in canine BPH and PCa.

Heat shock proteins (HSPs) 27, 72 and 73 in normal and pre-ulcerative mucosa of the gastric pars oesophagea in swine.

Heat shock proteins (HSPs), known to play a key role in cellular homeostasis, may also play a role in the defensive mechanisms of gastric mucosa. By means of appropriate immunohistochemical and immunobiochemical techniques, the expression of HSP27, HSP72 and HSP73 within the epithelium of normal and pre-ulcerative (hyperkeratinized) mucosa of the pars oesophagea of abattoir pigs was assessed. In normal mucosa, HSP72 and HSP73 expression was mainly limited to the basal epithelial cell layer, whereas HSP27 expression was consistently detected within the superficial epithelial cell layers. In hyperkeratinized mucosa, HSP72 and HSP73 immunoreactivity appeared to be more widespread, becoming very intense within epithelial cells affected by hydropic degeneration. Hyperkeratinized mucosa also showed HSP27 immunoreactivity, which was particularly intense in epithelial areas affected by hydropic degeneration. Western blot analysis confirmed HSP27, HSP72 and HSP73 expression in normal and in pre-ulcerative mucosa of the pars oesophagea. Semi-quantitative analysis showed that for all three HSPs the immunoreactivity was more intense in pre-ulcerative mucosa than in normal mucosa. The different expression patterns observed may have functional significance; further studies are needed, however, to define the role of HSPs in swine oesophagogastric lesions, the aetiology and pathogenesis of which are largely unknown.

Cytological, histological and ultrastructural nuclear features of monster cells in a canine carotid body carcinoma.

A 7-year-old female Shih-tzu dog was presented with severe dyspnoea. A large mass was palpated in the left cranial neck. Cytological examination of an aspirate sample revealed cells with marked anisokaryosis, giant elements and many bare nuclei. Scattered intact giant cells showed scant, granular cytoplasm and intranuclear inclusions. Histologically, neoplastic cells were subdivided into lobules by fine collagenous trabeculae. Numerous pleomorphic giant, or 'monster', cells were observed, showing a highly indented nuclear envelope, intranuclear cytoplasmic pseudoinclusions (ICPs) and 'ground-glass' nuclear appearance. Neoplastic emboli were present, but no distant metastases were detected grossly. Immunohistochemically, the neoplastic cells expressed synaptophysin and had variable expression of neuron-specific enolase and vimentin. The cells were negative for pan-cytokeratin, CAM 5.2, glial fibrillary acidic protein and S100. Nuclear abnormalities and cytoplasmic neurosecretory granules were noted ultrastructurally. These features were consistent with a diagnosis of carotid body carcinoma (chemodectoma). Monster cells with ICPs have not been documented previously in canine chemodectoma.

Immunohistochemical evaluation of heat shock protein expression in normal canine nerve and peripheral nerve sheath tumours.

Abnormal expression of heat shock proteins (HSPs) has been observed in many human neoplasms and such expression has prognostic, predictive and therapeutic implications. The aim of this study was to evaluate immunohistochemically the expression of HSP 27, HSP 32 and HSP 90 in normal canine peripheral nerves and in four benign and 15 malignant canine peripheral nerve sheath tumours (PNSTs). In normal nerve, all of the HSPs were detected in axons, epineurial fibroblasts and scattered Schwann cell bodies. Cytoplasmic expression of HSP 27 was more widespread and intense in benign PNSTs compared with malignant PNSTs (P <0.05). Widespread and intense nuclear expression of HSP 32 was also associated with benign tumours (P <0.01), while high HSP 90 immunoreactivity was detected in all tumours, suggesting that HSP 90 might represent a new therapeutic target.

Intracoelomic teratoma in a domestic duck (Anas platyrhynchos domesticus): a case report including immunohistochemistry and electron microscopy.

A female domestic duck (Anas platyrhynchos domesticus) suddenly died with abdominal distension and a large multilobulated mass within the coelomic cavity was found. Histologically and immunohistochemically, a benign mature tridermic teratoma was diagnosed and epithelial structures, cartilage, bone, myxoid tissue, adipocytes, muscle cells, cystic spaces lined by squamous epithelium, feather follicles, melanocytes and variable neural and glial differentiation were recognized. By electron microscopy, desmosomes, keratin bundles, dense core neurosecretory granules, aberrant Z-line material and Luse bodies were found. To our knowledge, this is the first report of tridermic benign intracoelomic teratoma of a duck in which an extensive immunohistochemical and electron microscopic examination has been performed and in which a common neural and glial differentiation has been demonstrated.

Xanthogranulomatous inflammation of the small bowel in a dog.

A case of xanthogranulomatous inflammation of the small bowel in a 12-year-old male American Staffordshire Terrier is described. Disseminated yellow-white nodules 2 to 3 mm in diameter bulging on the serosal surface of the small bowel, as well as on mesenteric tissue, were detected. Histopathologic examination revealed a nodular collection of foamy cells, mainly involving serosal and muscular layers, associated with necrotic areas, hemorrhages, neovascularization, variable numbers of reactive spindle cells, neutrophils, lymphocytes, plasma cells, and rare multinucleated giant cells. Transmural lymphangectasia and mucosal lymphoplasmacytic inflammation were also observed. Both Oil Red O stain and ultrastructural study revealed lipid droplets in the cytoplasm of foamy cells. Lysozyme immunoreactivity was detected in single as well as in clustered foamy cells, while smooth muscle actin was positive in spindle cells and scattered foamy elements. Lymphangectasia associated with lymphoplasmacytic enteritis suggests a component of lymphatic fluid stasis in the pathogenesis of such lesions.