This study aimed to investigate Coll-I, III, IV and elastin in canine normal prostate and PC, using Picrosirius red (PSR) and Immunohistochemical (IHC) analysis. Eight normal prostates and 10 PC from formalin-fixed, paraffin-embedded samples were used. Collagen fibers area was analyzed with ImageJ software. The distribution of Coll-I and Coll-III was approximately 80% around prostatic ducts and acini, 15% among smooth muscle and 5% surrounding blood vessels, in both normal prostate and PC. There was a higher median area of Coll-III in PC, when compared to normal prostatic tissue (p=0.001 for PSR and p= 0.05 for IHC). Immunostaining for Coll-IV was observed in the basal membrane of prostate acini, smooth muscle, blood vessels, and nerve fibers of normal and PC samples. Although there was no difference in Coll-IV area between normal tissue and PC, tumors with Gleason score 10 showed absence of Coll-IV, when compared to scores 6 and 8 (p=0.0095). Elastic fibers were found in the septa dividing the lobules and around the prostatic acini of normal samples, and was statistically higher in PC, compared to normal tissue (p=0.00229). Investigation of ECM components brings new information and should be correlated with prognosis in future studies.

Mammary neoplasm affects a population of intact and elderly female dogs and 50% are malignant. In order to study this disease, cell culture is as a promising preclinical model, creating the opportunity to deposit cell lines at a cell bank, allowing a great reproducibility of the assays and making the validation of the results more reliable. Another important aspect is the possibility to establish models for better understanding tumour characteristics, such as vasculogenic mimicry. Due the importance of cancer cell lines in preclinical models, this study aimed to establish and characterize primary cell lines from canine mammary gland tumours according to immunophenotype and tumorigenicity, and with its ability to form vasculogenic mimicry-like structures in vitro and in vivo. Cell cultures were evaluated for morphology, phenotype, vasculogenic mimicry and tumorigenicity abilities. We collected 17 primary mammary carcinoma and 3 metastasis and had a satisfactory result in 10 of them. All cell lines presented spindle shape or polygonal morphology and expressed concomitant pan-cytokeratin and cytokeratin 8/18. Four cell lines had vasculogenic mimicry ability in vitro and two of them showed in vivo tumorigenic potential and forming VM in the xenotransplant tumour. Cell characterization of those lines will help to create a database for more knowledge of mammary carcinomas in dogs, including studies of tumour behaviour and new therapeutic targets.

Canine mammary tumors (CMT) are the most common cancer in noncastrated female dogs. Interestingly, triple-negative tumors are the most common molecular subtype in female dogs. In this study, we proposed to evaluate the expression of VEGFR-2, PDGFR and microvascular density (MVD) in a group of metastatic and nonmetastatic triple-negative CMT and compare the expression based on clinical parameters. Twenty-six female dogs with triple-negative mammary tumors were divided into three groups: nonmetastatic tumors (NMT) (N=11), tumors with lymph node metastasis (LNM) (N=10) and tumors with lung metastasis (LM) (N=5). We observed increased VEGFR-2 expression in LNM compared with NMT and a positive correlation between tumor grade and VEGFR-2 expression. A positive correlation was noted between VEGFR-2 and PDGFR expression. Regarding microvascular density (MVD), we identified a higher number of vessels in primary tumors with lymph node metastasis and lung metastasis compared with tumors with no metastasis. The primary tumors with lung metastasis exhibited an increased MVD compared with carcinoma with lymph node metastasis. Overall, our results suggest a deregulation of VEGFR-2 and PDGFR and high MVD in metastatic tumors, indicating a role for angiogenesis in tumor progression.

The giant anteater (Myrmecophaga tridactyla) is a vulnerable specie from Central and South America and is considered extinct in Belize, Guatemala, El Salvador, and Uruguay. Therefore, studies describing the reproductive characteristics of this species are pivotal for its conservation. Thus, this study aimed to provide a morphological description of their female reproductive tissues. We collected tissue samples from six female giant anteaters, and performed gross, morphological, and histochemical analyses. Five adult and one young subjects were enrolled in the study. In the ovary, classifications were made according to the follicle and oocyte sizes: primordial, primary, secondary, early antral, or antral. Typical follicles with a single oocyte surrounded by a simple or stratified layer of cubic epithelium, atretic follicles, corpora lutea, corpora albicans, and ovarian cysts were also observed. No ovarian lesions were observed. By contrast, endometritis, metritis, mucometra, and endometrial cysts were identified in the uterus. Uterine alterations in these subjects were frequent and could affect reproduction.