Background: Human breast cancer is classified by gene expression profile into subtypes consisting of two hormone (oestrogen and/or progesterone) receptor-positive types (luminal-like A and luminal-like B) and three hormone receptor-negative types [human epidermal growth factor receptor 2-expressing, basal-like, and unclassified ("normal-like")]. Immunohistochemical surrogate panels are also proposed to potentially identify the molecular-based groups. The present study aimed to apply an immunohistochemical panel (anti-ER, -PR, -ERB-B2, -CK 5/6 and -CK14) in a series of canine malignant mammary tumours to verify the molecular-based classification, its correlation with invasion and grade, and its use as a prognostic aid in veterinary practice.Results: Thirty-five tumours with luminal pattern (ER+ and PR+) were subgrouped into 13 A type and 22 B type, if ERB-B2 positive or negative. Most luminal-like A and basal-like tumours were grade 1 carcinomas, while the percentage of luminal B tumours was higher in grades 2 and 3 (Pearson Chi-square P = 0.009). No difference in the percentage of molecular subtypes was found between simple and complex/mixed carcinomas (Pearson Chi-square P = 0.47). No significant results were obtained by survival analysis, even if basal-like tumours had a more favourable prognosis than luminal-like lesions.Conclusion: The panel of antibodies identified only three tumour groups (luminal-like A and B, and basal-like) in the dog. Even though canine mammary tumours may be a model of human breast cancer, the existence of the same carcinoma molecular subtypes in women awaits confirmation. Canine mammary carcinomas show high molecular heterogeneity, which would benefit from a classification based on molecular differences. Stage and grade showed independent associations with survival in the multivariate regression, while molecular subtype grouping and histological type did not show associations. This suggests that caution should be used when applying this classification to the dog, in which invasion and grade supply the most important prognostic information.

The definition “porcine respiratory disease complex” (PRDC) is used to indicate the current approach for presenting respiratory pathology in modern pig farming. PRDC includes pneumonias with variable pictures, mixed with both aerogenous and hematogenous forms with variable etiology, often multimicrobial, and influenced by environmental and management factors. The notion that many etiological agents of swine respiratory pathology are ubiquitous in the airways is commonly understood; however, their isolation or identification is not always associable with the current pathology. In this complex context, lung lesions registered at slaughterhouse or during necropsy, and supplemented by histological investigations, must be considered as powerful tools for assigning a prominent role to etiologic agents. In recent years, the goal of colocalizing causative agents with the lesions they produce has been frequently applied, and valid examples in routine diagnostics are those that indicate pulmonary involvement during porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) infections.

During the summer of 2013 seven Italian Tyrolean Grey calves were born with abnormally short limbs. Detailed clinical and pathological examination revealed similarities to chondrodysplastic dwarfism. Pedigree analysis showed a common founder, assuming autosomal monogenic recessive transmission of the defective allele. A positional cloning approach combining genome wide association and homozygosity mapping identified a single 1.6 Mb genomic region on BTA 6 that was associated with the disease. Whole genome re-sequencing of an affected calf revealed a single candidate causal mutation in the Ellis van Creveld syndrome 2 (EVC2) gene. This gene is known to be associated with chondrodysplastic dwarfism in Japanese Brown cattle, and dwarfism, abnormal nails and teeth, and dysostosis in humans with Ellis-van Creveld syndrome. Sanger sequencing confirmed the presence of a 2 bp deletion in exon 19 (c.2993_2994ACdel) that led to a premature stop codon in the coding sequence of bovine EVC2, and was concordant with the recessive pattern of inheritance in affected and carrier animals. This loss of function mutation confirms the important role of EVC2 in bone development. Genetic testing can now be used to eliminate this form of chondrodysplastic dwarfism from Tyrolean Grey cattle.

Myoepithelium is present in canine mammary tumors as resting and proliferative suprabasal and spindle and stellate interstitial cells. The aim of this paper was to evaluate a panel of markers for the identification of four different myoepithelial cell morphological types in the normal and neoplastic mammary gland and to investigate immunohistochemical changes from an epithelial to a mesenchymal phenotype. Cytokeratin 19 (CK19), cytokeratin 5/6 (CK5/6), cytokeratin 14 (CK14), estrogen receptor (ER), p63 protein, vimentin (VIM), andα-smooth muscle actin (Alpha-SMA) antibodies were used on 29 neoplasms (3 benign and 3 malignant myoepithelial tumors, 7 carcinomas in benign-mixed tumors and 16 complex carcinomas) and on normal tissue of mammary glands. All these antibodies were also tested on 3 mammary tissues from animals with no mammary pathology. The myoepithelial markers were well expressed in the suprabasal cells and gradually lost in the motile types, with the stellate cells maintaining only VIM expression typical of mesenchyma. ER labeled some resting and motile myoepithelial cells. On the basis of our results, we propose a transition from myoepithelial immotile cells into migratory fibroblast-like cells. This transition and the characterization of an immunohistochemical panel for resting and motile myoepithelial cells shed more light on the biological behavior of myoepithelial cells.

Placenta is essential for the development of the fetus, and its impaired function can lead to a negative outcome (i.e., neonatal mortality). In dogs, investigations on placenta histology and neonatal outcome in healthy bitches are lacking, and a contribution is provided in this study to emphasize the use of placenta histology in practice. Fifty-one placentas from 11 litters were collected during cesarean section, classified according to the litter size (large (L) or small (S)) and the outcome, this latter as healthy (Group 1) or dead within 7 days (Group 2). The placenta/puppy weight ratio (PPR) was calculated, and specimens were formalin-fixed and paraffin-wax embedded, and on the resulting histological slides, capillary density (CD) was quantified. Among necrosis, calcification, and intravascular leucocytes, only the presence of multifocal-confluent necrosis (significantly more frequent in Group 2) was associated with a higher risk of death within 7 days (odds ratio = 30.7). Mixed logistic regression ruled out the effect on death both of a bitch and cesarean type (programmed vs. emergency). PPR and CD values were associated with litter size; large litters had lower PPR (p < 0.01) and higher CD (p < 0.05) than small litters. The relationship between PPR and CD was negative and significant (p < 0.01). Necrosis was a frequent finding in canine placentas, but only when multifocal-confluent was it associated with a poor outcome. The litter size influenced PPR (lower in L) and CD (higher in L), and this is likely due to the plasticity of placenta adaptation.