Immunocytochemical differentiation of canine mesenchymal tumors in cytologic imprint preparations

Localized pleural mesothelioma in a dog

Malignant mesotheliomas with localized growth are extremely rare in dogs. A 9-year-old male dog presented with a localized tumour that originated from the parietal pleura and had polypoid growth in the thoracic cavity. Histological examination revealed that the tumour consisted of tubular formations with scattered cysts and minimal papillary growth pattern. Neoplastic cells were immunopositive for mesothelial markers (calretinin and Wilms' tumour gene 1) and negative for carcinoma markers (thyroid transcription factor 1 and tumour protein 63). The animal was alive with no recurrence or metastasis/dissemination 11 months after surgery. To the best of our knowledge, this is the first report of a localized mesothelioma in a dog without metastasis/dissemination and highlights the value of mesothelial markers for an accurate diagnosis.

Comparison of effusion cell block and biopsy immunohistochemistry in mesothelial hyperplasia, mesothelioma, and carcinoma in dogs

BACKGROUND

Determining the cause of effusions is challenging and might require a biopsy. Whether cell blocks from effusions are representative of biopsies requires investigation. A previously developed immunohistochemical panel aids in the differentiation of hyperplastic and neoplastic mesothelium in canine biopsies but has not been investigated in effusions.

OBJECTIVES

The study aimed to assess cell blocks as an alternative to biopsies and determine whether immunohistochemistry helps distinguish hyperplastic mesothelium, mesothelioma, and carcinoma.

METHODS

Effusions and biopsies were collected from five dogs with mesothelial hyperplasia (group MH), six with mesothelioma (group M), and five with carcinoma (group C). Immunohistochemistry (IHC) for cytokeratin, vimentin, Wilm's tumor protein 1 (WT1), desmin, glucose transporter 1 (GLUT1), and insulin-like growth factor II mRNA-binding protein 3 (IMP3) was performed. Sections were scored for staining intensity and the percentage of positively stained cells.

RESULTS

In paired cell blocks and biopsies, vimentin and WT1 staining were positively correlated for intensity and the percentage of positive cells, although not all paired results were identical. The intensity of IMP3 staining in cell blocks was higher in group M than in group C (P = 0.012), and WT1 staining was higher in group MH than in group C (P = 0.020). For biopsies, the intensity of WT1 staining was higher in group MH than in group C (P = 0.031). In group C, WT1 was negative in all cell blocks and biopsies, and desmin was negative in four of five cases.

CONCLUSIONS

IHC results for the cell blocks and biopsies were comparable for potentially useful markers, such as WT1, which helped discriminate between groups. IHC provided additional information, although results were not always definitive. Further studies on a larger population are required.

The epigallocatechin gallate derivative Y6 reduces the cardiotoxicity and enhances the efficacy of daunorubicin against human hepatocellular carcinoma by inhibiting carbonyl reductase 1 expression

ETHNOPHARMACOLOGICAL RELEVANCE

Green tea is the most ancient and popular beverage worldwide and its main constituent epigallocatechin-3-gallate (EGCG) has a potential role in the management of cancer through the modulation of cell signaling pathways. However, EGCG is frangible to oxidation and exhibits low lipid solubility and bioavailability, and we synthesized a derivative of EGCG in an attempt to overcome these limitations.

AIM OF THE STUDY

The anthracycline antibiotic daunorubicin (DNR) is a potent anticancer agent. However, its severe cardiotoxic limits its clinical efficacy. Human carbonyl reductase 1 (CBR1) is one of the most effective human reductases for producing hydroxyl metabolites and thus may be involved in increasing the cardiotoxicity and decreasing the antineoplastic effect of anthracycline antibiotics. Accordingly, in this study, we investigated the co-therapeutic effect of Y6, a novel and potent adjuvant obtained by optimization of the structure of EGCG.

MATERIAL AND METHODS

The cellular concentrations of DNR and its metabolite DNRol were measured by HPLC to determine the effects of EGCG and Y6 on the inhibition of DNRol formation. The cytotoxic effects of EGCG and Y6 were tested by MTT assay in order to identify non-toxic concentrations of them. To understand their antitumor and cardioprotective mechanisms, hypoxia-inducible factor-1α (HIF-1α) and CBR1 protein expression was measured via Western blotting and immunohistochemical staining while gene expression was analyzed using RT-PCR. Moreover, PI3K/AKT and MEK/ERK signaling pathways were analyzed via Western blotting. HepG2 xenograft model was used to detect the effects of EGCG and Y6 on the antitumor activity and cardiotoxicity of DNR in vivo. Finally, to obtain further insight into the interactions of Y6 and EGCG with HIF-1α and CBR1, we performed a molecular modeling.

RESULTS

Y6(10 μg/ml or 55 mg/kg) decreased the expression of HIF-1α and CBR1 at both the mRNA and protein levels during combined drug therapy in vitro as well as in vivo, thereby inhibiting formation of the metabolite DNRol from DNR, with the mechanisms being related to PI3K/AKT and MEK/ERK signaling inhibition. In a human carcinoma xenograft model established with subcutaneous HepG2 cells, Y6(55 mg/kg) enhanced the antitumor effect and reduced the cardiotoxicity of DNR more effectively than EGCG(40 mg/kg).

CONCLUSIONS

Y6 has the ability to inhibit CBR1 expression through the coordinate inhibition of PI3K/AKT and MEK/ERK signaling, then synergistically enhances the antitumor effect and reduces the cardiotoxicity of DNR.

The cell tube block technique and an immunohistochemistry panel including Wilms tumor 1 to assist in diagnosing cavitary effusions in dogs and cats

BACKGROUND

Cell blocks and immunohistochemistry (IHC) are increasingly recognized as being complementary tools for cytologic diagnostics, especially for neoplastic diseases.

OBJECTIVES

The study aimed to evaluate the utility of cell tube block (CTB) IHC for refining the diagnosis of effusions in dogs and cats.

METHODS

Cavitary effusions (n = 25) from dogs and cats classified by cytology as reactive, neoplastic, borderline (suspicious of neoplasia), and chylous were studied. CTB sections were stained with H&E, and immunostained with PAX-5, CD3, pancytokeratin (CK), vimentin, and Wilms tumor 1 protein (WT1) antibodies, according to the cytologic diagnoses. A histologic case series of confirmed normal, reactive, and neoplastic mesothelium and several different carcinomas were included to test the utility of WT1 as a marker of mesothelial cells.

RESULTS

CTBs had a layered appearance with reduced background staining. CD3 and PAX5 immunolabeling allowed immunophenotype assessment in all of the lymphoma cases. In carcinomatous effusions, neoplastic cells were CK-positive, WT1-negative, and vimentin-negative (except for two cases). Wilms tumor 1 protein was positive in the nuclei of normal, reactive, and neoplastic mesothelial cells, and ovarian carcinomatous cells. Other carcinomas and lymphomas were negative.

CONCLUSIONS

CTBs are valuable tools to assist in making a diagnosis of cavitary effusions in dogs and cats, and WT1 is a promising marker to differentiate mesothelial from carcinomatous cells.

Rapid multiple immunofluorescent staining for the simultaneous detection of cytokeratin and vimentin in the cytology of canine tumors

BACKGROUND

Immunocytochemistry (ICC) is utilized as an advanced technique in veterinary cytology. In tumor diagnosis, cytokeratin and vimentin are markers used to distinguish the origin of tumor cells. Standard enzyme-based ICC has limitations in clinical use; and therefore, more convenient and reliable methods are needed.

OBJECTIVES

The purpose of this study was to develop a rapid multiple immunofluorescent (RMIF) detection method for dual cytokeratin and vimentin staining on cytology slides in dogs.

METHODS

Air-dried smear samples from solid tumors and sediments of pleural effusions were prepared from dogs (n = 14) that were admitted to the Veterinary Teaching Hospital, Kagoshima University, Japan. Mouse monoclonal anti-human cytokeratin (AE1/AE3) and rabbit monoclonal anti-human vimentin (SP20) antibodies were used as primary antibodies, followed by staining with Alexa Fluor-conjugated secondary antibodies. Staining using the RMIF method was compared with enzyme-based ICC staining.

RESULTS

Rapid multiple immunofluorescent immunostaining was clear and specific in the evaluated smears, whereas the enzyme-based ICC showed nonspecific signals. By using the RMIF staining method, epithelial cells, mesenchymal cells, and mesothelial cells could be classified on a single smear of a pleural effusion. In smears of lymph nodes with epithelial tumor metastases, the RMIF method successfully detected metastatic epithelial tumor cells.

CONCLUSIONS

The RMIF method might be a useful tool for diagnostic cytology in veterinary medicine.

Using cytology to increase small animal practice revenue

Diagnostic cytology is a useful, noninvasive test with practical foundations in high-quality medicine and applications to practice building. Cytology will generate practice revenue whether assessed in-house or sent to a clinical pathologist. Thorough in-house evaluation is adequate in some cases, but expert opinion is important in many cases. Specimen slides should at least be reviewed in-house for assessment of cellularity and potential artifacts before submission to a reference laboratory. Reference laboratories also provide special stains and advanced molecular diagnostics to help further characterize many neoplastic processes, search for organisms, identify pigments, and address other important aspects of the lesion.

Malignant Melanoma in Pleural Effusion in a 14-Year-Old Cat

Case details A 14-year-old female cat presented with signs of respiratory distress. Pleural fluid was found on radiographic assessment. Cytologic evaluation of the fluid revealed malignant melanocytosis. The cat had a previous history of a recurrent malignant melanoma near the base of the right ear. Due to declining clinical condition, the cat was euthanized.

Clinical significance Cutaneous malignant melanomas (or melanosarcomas) are uncommon neoplasms in cats, and knowledge is limited. As far as the authors are aware, there are no previous reports in the veterinary literature of malignant melanocytes being identified in pleural effusion in cats, as they have in dogs. This report suggests that, despite conflicting information in the literature regarding the clinical behavior of cutaneous melanomas in cats, these tumors are capable of recurrence and metastasis. Aggressive treatment may be necessary even, as in this case, if the tumor is well differentiated on histopathology.