Flow cytometric DNA ploidy analysis in canine transitional cell carcinoma of urinary bladders

DNA aneuploidy and centrosome amplification in canine tumor cell lines

DNA aneuploidy, the altered DNA content of a cell, is a common feature of canine tumors. However, it is unclear whether aneuploid DNA in canine tumor cells show centrosome amplification (CA), which contributes to numerical and structural chromosome aberrations that result in DNA aneuploidy. Here, we evaluated whether DNA aneuploidy and CA occur concurrently in canine tumor cell lines. Centrosome numbers were evaluated in 18 canine tumor cell lines by immunocytochemistry with anti-γ-tubulin antibody, and DNA content was evaluated by flow cytometry using propidium iodide. A total of 15 cell lines showed DNA aneuploidy, and CA was observed in 5 of these 15 cell lines. Together, our results suggest that DNA aneuploidy in canine tumor cells might be explained at least in part by CA. In addition, cell lines with CA may be useful tools to examine the detailed relationship between CA and DNA aneuploidy and the molecular mechanism of CA in canine tumor.

Urologic Oncology

Primary renal tumors are an uncommon diagnosis in small animals. Presentation, treatment, and prognosis depend on tumor type. Surgery with or without chemotherapy are the mainstays of treatment. Transitional cell carcinoma is the most common tumor of the urinary system. Clinical signs include hematuria, stranguria, and pollakiuria. Metastatic disease can develop over time within medial iliac lymph nodes, lungs, and vertebrae. Treatment of transitional cell carcinoma centers on chemotherapy with mitoxantrone, vinblastine, or carboplatin. Other agents used with success, include toceranib phosphate and chlorambucil. Interventional surgery, such as stenting and laser ablation, is used in a palliative setting addressing urinary obstruction.

Flow Cytometric Characterization of S-phase Fraction and Ploidy in Lymph Node Aspirates from Dogs with Lymphoma

Canine lymphoma is a multifaceted disease encompassing numerous entities with different prognosis. Objective assessment of the proliferation rate is of importance from the pathological and clinical perspectives. Different methods have been described in the literature to assess proliferation rate, including evaluation of Ki67 expression in fresh lymph node (LN) aspirates measured by flow cytometry (FC). This test has a high accuracy in discriminating between low- and high-grade lymphomas, and provides prognostic information among high-grade B-cell lymphomas. DNA content analysis is less expensive and suitable for well-preserved samples. We describe DNA-content analysis using LN aspirates from 112 dogs with lymphoma. S-phase fraction (SPF) accurately discriminated between low- and high-grade lymphomas, with 3.15% being the best discriminating cut-off value. SPF values strongly correlated with Ki67 expression as assessed by FC. Survival analyses were restricted to 33 dogs with high-grade B-cell lymphoma receiving standardized multi-agent chemotherapy, but no significant result was obtained for SPF. We also describe a subset of aneuploid cases and their respective follow-up. We conclude that DNA content analysis may be combined with morphological examination of LN aspirates to improve the objectivity in lymphoma subtype classification in dogs. Further studies are needed to assess the possible prognostic role of SPF and ploidy status within specific lymphoma subtypes in dogs.

A cultured approach to canine urothelial carcinoma: molecular characterization of five cell lines

Background

Urothelial carcinoma (UC), also known as transitional cell carcinoma (TCC), of the bladder is the most common neoplasm affecting the canine urogenital system. To facilitate study of the disease in vitro, cell line models have been established from primary tumor biopsies. Their resemblance to the primary disease, however, has not been well defined. In the present study, we evaluated five canine UC cell lines via oligonucleotide array comparative genomic hybridization (oaCGH), fluorescence in situ hybridization (FISH), and gene expression analysis.

Results

Comparison of genome wide DNA copy number profiles of the cell lines with primary biopsy specimens revealed redundancies in genomic aberrations, indicating that the cell lines retain the gross genomic architecture of primary tumors. As in the primary tumors, gain of canine chromosomes 13 and 36 and loss of chromosome 19 were among the most frequent aberrations evident in the cell lines. FISH analysis revealed chromosome structural aberrations, including tandem duplications, bi-armed chromosomes, and chromosome fusions, suggesting genome instability during neoplastic transformation. Gene expression profiling highlighted numerous differentially expressed genes, including many previously shown as dysregulated in primary canine UC and human bladder cancer. Pathway enrichment analysis emphasized pathways suspected to be at the crux of UC pathogenesis, including xenobiotic and lipid compound metabolism.

Conclusions

These data support valid use of the canine UC cell lines evaluated by confirming they provide an accurate and practical means to interrogate the UC at a molecular level. Moreover, the cell lines may provide a valuable model for furthering our understanding of aberrant metabolic pathways in UC development.

Electronic supplementary material

The online version of this article (doi:10.1186/s40575-015-0028-3) contains supplementary material, which is available to authorized users.

Diagnostic pathology for the cancer patient

It is necessary to have a cooperative relationship between the clinician and the pathologist, because information from both is critical for determining the best case management and favorable prognosis. The principle roles of the veterinary pathologist are to describe the submitted tissues, to determine the nature of the tumor, and to assess completeness of surgical margins. Recently, the Council of the American College of Veterinary Pathologists (ACVP) appointed an ad hoc committee on oncology to evaluate oncologists' needs by polling members of the Veterinary Cancer Society (VCS). The committee's vision was to review morphologic, immunologic, and molecular techniques so that veterinary pathologists could meet the current and future diagnostic and prognostic needs of oncologic veterinarians. The factors determined to be most important to the VCS members in selecting a diagnostic pathology provider included, in order of importance: (1) reliability of results; (2) short turnaround-time; (3) easy access for consultation; (4) rapport with pathologist; (5) convenience of service; and (6) cost of service. This manuscript will attempt to review improved morphologic, immunologic, and molecular techniques to provide for the future diagnostic and prognostic needs of oncologic veterinarians.

Evaluation of a bladder tumor antigen test for the diagnosis of lower urinary tract malignancies in dogs

OBJECTIVE

To evaluate the use of a human bladder tumor antigen test for diagnosis of lower urinary tract malignancies in dogs.

SAMPLE POPULATION

Urine samples from dogs without urinary tract abnormalities (n = 18) and from dogs with lower urinary tract neoplasia (20) or nonmalignant urinary tract disease (16).

PROCEDURE

Test results were compared among groups and among 3 observers. The effects of urine pH and specific gravity, degree of hematuria, and storage temperature and time of urine samples on test results were also assessed.

RESULTS

Test sensitivity and specificity were 90 and 94.4%, respectively, for differentiating dogs with lower urinary tract neoplasia from dogs without abnormalities. However, specificity decreased to 35% for differentiating dogs with neoplasia from dogs with nonmalignant urinary tract disease. In dogs with neoplasia, results were significantly affected by degree of hematuria. However, addition of blood to urine from dogs without hematuria had no significant effect on test results. Although intraobserver variation was significant, urine pH, specific gravity, or storage time or temperature had no significant effect on results.

CONCLUSIONS AND CLINICAL RELEVANCE

Although this bladder tumor antigen test was sensitive for differentiating dogs with malignancies of the lower urinary tract from dogs without urinary tract disease, it was not specific for differentiating dogs with neoplasia from dogs with other lower urinary tract abnormalities. It cannot, therefore, be recommended as a definitive diagnostic aid for the detection of lower urinary tract malignancies in dogs.

Immunoreactivity of canine transitional cell carcinoma of the urinary bladder with monoclonal antibodies to tumor-associated glycoprotein 72

Tumor-associated glycoprotein 72 (TAG-72) is a large, high molecular weight, mucinlike antigen that is expressed in a wide variety of human carcinomas. Three different TAG-72 monoclonal antibodies (MAbs), designated B72.3, CC49, and CC83, were applied to the following archived samples from the dog: 1) 51 transitional cell carcinomas of the urinary bladder, 2) 15 hyperplastic/inflamed urinary bladders, and 3) eight normal urinary bladders. Immunoreactivity was detected with an avidin-biotin complex immunoperoxidase method. Fifty-three percent (27/51) of transitional cell carcinomas were positive (> or = 5% staining) for MAb B72.3. MAb B72.3 staining of these transitional cell carcinomas did not statistically correlate with any of the examined features of malignancy, including histologic grade, clinical stage, DNA ploidy, or presence of vascular/lymphatic invasion. In regard to the staining of transitional cell carcinoma by the other two TAG-72 antibodies, 53% (27/51) of the samples were positive for MAb CC83 and 63% (32/51) were positive for MAb CC49. The finding that similar populations of neoplastic urothelial cells in serial sections from the same neoplasm stained with all three TAG-72 antibodies supports the hypothesis that an antigen similar to TAG-72 was expressed in canine transitional cell carcinoma. None of the normal urinary bladders nor any of the hyperplastic/inflamed urinary bladders stained with any of the three TAG-72 antibodies tested. The results of these studies demonstrated that the staining of canine transitional cell carcinoma with all three TAG-72 antibodies was specific for neoplastic urothelial cells and that an antigen similar to TAG-72 was expressed.