Endocrine involvement in hepatic glycogen storage diseases: pathophysiology and implications for care

Hepatic glycogen storage diseases constitute a group of disorders due to defects in the enzymes and transporters involved in glycogen breakdown and synthesis in the liver. Although hypoglycemia and hepatomegaly are the primary manifestations of (most of) hepatic GSDs, involvement of the endocrine system has been reported at multiple levels in individuals with hepatic GSDs. While some endocrine abnormalities (e.g., hypothalamic‑pituitary axis dysfunction in GSD I) can be direct consequence of the genetic defect itself, others (e.g., osteopenia in GSD Ib, insulin-resistance in GSD I and GSD III) may be triggered by the (dietary/medical) treatment. Being aware of the endocrine abnormalities occurring in hepatic GSDs is essential (1) to provide optimized medical care to this group of individuals and (2) to drive research aiming at understanding the disease pathophysiology. In this review, a thorough description of the endocrine manifestations in individuals with hepatic GSDs is presented, including pathophysiological and clinical implications.

Prognostic impact of Ki-67 in canine splenic hemangiosarcoma: A preliminary study

Canine splenic hemangiosarcoma has a high metastatic rate and short survival time. Currently, the main prognostic parameters are tumor stage and therapy, while data on histologic parameters, such as grade and Ki-67 expression, are scarce. The aims of this study were to compare two methods of assessment of Ki-67, verify their prognostic impact, and define a threshold value based on survival. Thirty-one cases of histologically diagnosed canine splenic hemangiosarcoma, which were treated with splenectomy and had full staging and follow-up information, were collected. Three were stage I, 17 stage II, and 11 stage III. The mean mitotic count (MC) was 23.9 (standard deviation [SD]: 22.1) and the median was 15 (range, 1-93). Immunohistochemistry for Ki-67 was performed, the Ki-67 labeling index (Ki-67LI) was assessed as a percentage of positive neoplastic nuclei per ≥500 cell, and the Ki-67 count (KI-67C) was defined as the average number of positive nuclei using a 1 cm2 optical grid performed in 5, 40× fields. The mean Ki-67LI and Ki-67C were 56.4% (SD: 38.7) and 27.2 (SD: 12.9) and medians were 51% (range, 8.2-55.2) and 26 (range, 5.5-148), respectively. Using a cut-off of 56% and 9, respectively, Kaplan-Meier survival curves showed an association of overall survival with Ki-67LI and MC. In addition to clinical stage, Ki-67LI maintained its prognostic value on multivariate analysis, supporting the role of Ki-67LI as an independent prognostic parameter. Based on these results, we propose a diagnostically applicable cut-off value of 56% for Ki-67LI as a prognostic parameter for canine splenic hemangiosarcoma.

Cutaneous Canine Mast Cell Tumor: The Use of Proliferative Markers (Ki-67 and Ki-67 × AgNOR) in Cytological Samples for Diagnosis and Prognosis

A cytological grading system for canine mast cell tumors (MCTs) has been developed, but its integration into clinical routine has been hindered due to its diagnostic limitations. The aim of this study was to assess the prognostic value of Ki-67 and argyrophilic nucleolar organizing region (AgNOR) markers in cytological MCT samples and to determine cut-off values for these markers in correlation with histopathological grading. Cytological samples were collected prior to surgical excision, and histopathological samples were obtained postsurgery from 45 dogs diagnosed with cutaneous mast cell tumors (MCTs). The cytological specimens were classified using a two-tier grading system, and their Ki-67 (average immunopositive nuclei per 100 cells) and AgNOR (average AgNOR counts per 100 nuclei) signaling was assessed. Through receiver operating characteristic (ROC) analysis, cut-off values for Ki-67 and Ki-67 × AgNOR were determined to better align with histopathological grading (classified as low or high grade according to Kiupel's scoring system). Without the inclusion of proliferative markers, there was a 73% agreement between cytological and histopathological grading. The prediction of histopathological grade was slightly more accurate when assessing Ki-67 and Ki-67 × AgNOR signaling in cytological specimens (75% and 80%, respectively) compared to the initial cytological grading. The cytological assessment of canine MCTs proves beneficial for the initial evaluation, and the incorporation of the evaluation of Ki-67 and AgNOR markers may assist in identifying diagnostically highly malignant MCTs.

Upregulation of miR-21 and pro-inflammatory cytokine genes IL-6 and TNF-α in promoting a pro-tumorigenic microenvironment in canine mammary carcinomas

This study evaluated the gene expression of the pro-inflammatory cytokines, interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in canine mammary tumors (CMTs), and correlated them with gene expression of miRNAs expected to regulate the secretion of pro-inflammatory cytokines within the tumor microenvironment (TME). Furthermore, gene expression of cytokines and miRNAs involved in tumor cell proliferation and invasion (i.e. miR-21; miR-124; miR-145) were correlated with tumor proliferation index (Ki67 index) to determine the prognostic value in CMTs. Twenty-six canine mammary samples were used, including 22 CMTs and 4 control samples. MiR-21, IL-6 and TNF-α were upregulated in mammary carcinomas compared with controls (p < 0.05). MiR-146b was downregulated in CMTs compared with control cases (p < 0.05). IL-6 expression showed a significant positive correlation with miR-21 and a negative correlation with miR-146b; while, TNF-α gene expression was positively correlated with miR-21 and miR-145 in mammary carcinomas. In carcinomas, the Ki67 index correlated positively with gene expression of IL-6 and miR-21 and negatively correlated with miR-145 and miR-146b. Specifically, gene expression of IL-6 and miR-21 was positively correlated with ki67 index >33.3%, whereas, expression of miR-145 and miR-146b was negatively correlated with ki67 index <33.3%. Results reinforce the concept of interaction between tumor cells and inflammatory cells within the TME, with a central role of IL-6 and TNF-α. Since the upregulation of miR-21 reflects the gene overexpression of interleukins and the high proliferation index of tumor cells, this miRNA may be considered a biomarker with prognostic value in CMTs.

SGCD Missense Variant in a Lagotto Romagnolo Dog with Autosomal Recessively Inherited Limb-Girdle Muscular Dystrophy

An 8-month-old female Lagotto Romagnolo dog was presented for a 1-month history of an initial severe reluctance to move, rapidly progressing to a marked stiff gait and progressive muscular weakness and evolving to tetraparesis, which persuaded the owner to request euthanasia. A primary muscle pathology was supported by necropsy and histopathological findings. Macroscopically, the muscles were moderately atrophic, except for the diaphragm and the neck muscles, which were markedly thickened. Histologically, all the skeletal muscles examined showed atrophy, hypertrophy, necrosis with calcification of the fibers, and mild fibrosis and inflammation. On immunohistochemistry, all three dystrophin domains and sarcoglycan proteins were absent. On Western blot analysis, no band was present for delta sarcoglycan. We sequenced the genome of the affected dog and compared the data to more than 900 control genomes of different dog breeds. Genetic analysis revealed a homozygous private protein-changing variant in the SGCD gene encoding delta- sarcoglycan in the affected dog. The variant was predicted to induce a SGCD:p.(Leu242Pro) change in the protein. In silico tools predicted the change to be deleterious. Other 770 Lagotto Romagnolo dogs were genotyped for the variant and all found to be homozygous wild type. Based on current knowledge of gene function in other mammalian species, including humans, hamsters, and dogs, we propose the SGCD missense variant as the causative variant of the observed form of muscular dystrophy in the index case. The absence of the variant allele in the Lagotto Romagnolo breeding population indicates a rare allele that has appeared recently.

Epigenetics in Canine Mammary Tumors: Upregulation of miR-18a and miR-18b Oncogenes Is Associated with Decreased ERS1 Target mRNA Expression and ERα Immunoexpression in Highly Proliferating Carcinomas

The expression of miRNAs is one of the main epigenetic mechanisms responsible for the regulation of gene expression in mammals, and in cancer, miRNAs participate by regulating the expression of protein-coding cancer-associated genes. In canine mammary tumors (CMTs), the ESR1 gene encodes for ERα, and represents a major target gene for miR-18a and miR-18b, previously found to be overexpressed in mammary carcinomas. A loss in ERα expression in CMTs is commonly associated with poor prognosis, and it is noteworthy that the downregulation of the ESR1 would appear to be more epigenetic than genetic in nature. In this study, the expression of ESR1 mRNA in formalin-fixed, paraffin-embedded (FFPE) canine mammary tumors (CMTs) was evaluated and compared with the expression levels of miR18a and miR18b, both assessed via RT-qPCR. Furthermore, the possible correlation between the miRNA expression data and the immunohistochemical prognostic factors (ERα immunoexpression; Ki67 proliferative index) was explored. A total of twenty-six FFPE mammary samples were used, including 22 CMTs (7 benign; 15 malignant) and four control samples (three normal mammary glands and one case of lobular hyperplasia). The obtained results demonstrate that miR-18a and miR-18b are upregulated in malignant CMTs, negatively correlating with the expression of target ESR1 mRNA. Of note, the upregulation of miRNAs strictly reflects the progressive loss of ERα immunoexpression and increased tumor cell proliferation as measured using the Ki67 index. The results suggest a central role of miR-18a and miR-18b in the pathophysiology of canine mammary tumors as potential epigenetic mechanisms involved in ERα downregulation. Moreover, as miRNA expression reflects ERα protein status and a high proliferative index, miR-18a and miR-18b may represent promising biomarkers with prognostic value. More detailed investigations on a larger number of cases are needed to better understand the influence of these miRNAs in canine mammary tumors.

Validation of p53 Immunohistochemistry (PAb240 Clone) in Canine Tumors with Next-Generation Sequencing (NGS) Analysis

In human medicine, p53 immunohistochemistry (IHC) is a common method that is used for the identification of tumors with TP53 mutations. In veterinary medicine, several studies have performed IHC for p53 in canine tumors, but it is not known how well it actually predicts the mutation. The aim of this study was to estimate the accuracy of the IHC method for p53 (clone PAb240) using a lab-developed NGS panel to analyze TP53 mutations in a subset of malignant tumors in dogs. A total of 176 tumors were analyzed with IHC and then 41 were subjected to NGS analysis; among them, 15 were IHC positive and 26 were negative, and 16 out of 41 (39%) were found to be inadequate for NGS analysis. Excluding the non-evaluable cases at NGS, of the remaining eight IHC-positive cases, six were mutants and two were wild-type. Among the 17 IHC-negative cases, 13 were wild type, and 4 were mutants. The sensitivity was 60%, specificity was 86.7%, and the accuracy was 76%. These results suggest that when using IHC for p53 with this specific antibody to predict mutation, up to 25% wrong predictions can be expected.

RT-qPCR Expression Profiles of Selected Oncogenic and Oncosuppressor miRNAs in Formalin-Fixed, Paraffin-Embedded Canine Mammary Tumors

MicroRNAs (miRNAs) can act as oncogenes or oncosuppressor genes, and their involvement in nearly all cancer-associated processes makes these small molecules promising diagnostic and prognostic biomarkers in cancer, as well as specific targets for cancer therapy. This study aimed to investigate the expression of 7 miRNAs (miR-18a, miR-18b, miR-22, miR-124, miR-145, miR-21, miR-146b) in formalin-fixed, paraffin-embedded canine mammary tumors (CMTs) by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Twenty-six mammary samples were selected, including 22 CMTs (7 benign; 15 malignant) and 4 control samples (3 normal mammary gland and 1 case of lobular hyperplasia). Oncogenic miR-18a, miR-18b and miR-21 were significantly upregulated in malignant tumors compared with control tissues (p < 0.05). Conversely, oncosuppressor miR-146b was significantly downregulated in benign and malignant mammary tumors compared with control samples (p < 0.05) while, no group-related differences in the expression levels of miR-22, miR-124 and miR-145 were found (p > 0.05). Upregulated miRNAs found here, may regulate genes involved in receptor-mediated carcinogenesis and proteoglycan remodeling in cancer; while miRNA with reduced expression can regulate genes involved in Toll-like receptor and MAPK signaling pathways. According to the results obtained in the current study, the oncogenic and oncosuppressor miRNAs analyzed here are dysregulated in CMTs and the dysregulation of miRNA targets may lead to specific altered cellular processes and key pathways involved in carcinogenesis. Of note, since oncogenic miRNAs predicted to regulate neoplastic cell proliferation and hormonal activities, they may play an active role in neoplastic transformation and/or progression, having mechanistic and prognostic relevance in CMTs.

Reproducibility and Feasibility of Classification and National Guidelines for Histological Diagnosis of Canine Mammary Gland Tumours: A Multi-Institutional Ring Study

Simple Summary

Tumours of the mammary gland are common in humans, as in canine species. They are very heterogenous with numerous morphological variants and different biologic behaviours. In the last few decades, several efforts have been made to classify these tumours histologically and establish the level of malignancy by using histologic grading systems. However, reproducibility and diagnostic agreement of such classification and grading have been only rarely assessed. In this study, we tested the variability in diagnoses performed by 15 pathologists using the same classification and grading system. Prior to the study, pathologists agreed on guidelines regarding how to apply these systems. Pathologists worked blindly on 36 digital histologic slides of canine mammary tumours. The agreement was statistically analysed using Cohen’s kappa coefficient that, when equal to 1, indicates perfect agreement. The overall agreement in the identification of hyperplastic-dysplastic/benign/malignant lesions was substantial (kappa 0.76), while outcomes on morphological classification had only a moderate agreement (k = 0.54). Tumour grade assigned by pathologists was the least concordant and kappa could not be calculated. Although promising, the results underline that each diagnostic/grading system should be assessed and optimized for standardization and high diagnostic agreement.

Abstract

Histological diagnosis of Canine Mammary Tumours (CMTs) provides the basis for proper treatment and follow-up. Nowadays, its accuracy is poorly understood and variable interpretation of histological criteria leads to a lack of standardisation and impossibility to compare studies. This study aimed to quantify the reproducibility of histological diagnosis and grading in CMTs. A blinded ring test on 36 CMTs was performed by 15 veterinary pathologists with different levels of education, after discussion of critical points on the Davis-Thompson Foundation Classification and providing consensus guidelines. Kappa statistics were used to compare the interobserver variability. The overall concordance rate of diagnostic interpretations of WP on identification of hyperplasia-dysplasia/benign/malignant lesions showed a substantial agreement (average k ranging from 0.66 to 0.82, with a k-combined of 0.76). Instead, outcomes on ICD-O-3.2 morphological code /diagnosis of histotype had only a moderate agreement (average k ranging from 0.44 and 0.64, with a k-combined of 0.54). The results demonstrated that standardised classification and consensus guidelines can produce moderate to substantial agreement; however, further efforts are needed to increase this agreement in distinguishing benign versus malignant lesions and in histological grading.

Canine and feline in situ mammary carcinoma: A comparative review

Carcinoma in situ of the breast is a well-known entity in humans. In veterinary medicine, particularly in canine and feline mammary literature, there is no agreement whether the term in situ should be used to indicate a specific carcinoma histotype or the noninvasive status of a carcinoma of any histotype. Moreover, in the most recent histologic classification of mammary tumors published by the Davis-Thompson Foundation, it is suggested to abandon the term carcinoma in situ given the lack of standardized criteria defining this entity, replacing it with epitheliosis or ductal/lobular hyperplasia with severe atypia. This publication presents a critical review of the term in situ in human and veterinary medicine considering the evolution of the term over the years and its heterogeneous use by different authors, including variations in immunohistochemical markers for classification. This review aims to point out the lack of uniformity in the nomenclature and classification issues in veterinary medicine regarding the use of the term in situ, laying the ground for a process of standardization in future publications.

Standardized approach for evaluating tumor infiltrating lymphocytes in canine mammary carcinoma: Spatial distribution and score as relevant features of tumor malignancy

Neoplastic cells, through immunoediting mechanisms, can establish a state of immunosuppression to evade host immune defenses. The aims of this study were: (1) to validate a standard method for assessing tumor infiltrating lymphocytes (TILs) in canine mammary carcinoma by applying international human breast cancer guidelines; (2) to investigate if the TIL population was composed of a subset of regulatory T lymphocytes (Tregs); and (3) to evaluate the relationship between the number of TILs and Tregs and the biological behavior of the tumors. One hundred and twenty-nine canine mammary tumors were retrospectively selected for this study. Histological diagnosis, grading and histological evaluation of TILs was performed on hematoxylin and eosin-stained sections. TILs were evaluated using a three-tier semiquantitative method, previously validated in human medicine, based on the percentage of TILs (0-10%, 11-40% and 41-90%). Lymphocyte immunophenotype was confirmed by CD3 and CD79, while an anti-FoxP3 antibody was used to determine the presence of Tregs. The number of stromal TILs and invasive front TILs significantly correlated with each other (P<0.0001) and increased with increasing histological grade (P=0.002 and P=0.004, respectively). A subset of TILs was composed of FOXP3⁺ Tregs. Stromal Tregs and invasive front Tregs were associated with stromal TILs and invasive front TILs (P=0.03; P=0.01 and P=0.003; P=0.007, respectively). In conclusion, in canine mammary carcinomas, an increased number of stromal and invasive front TILs is associated with increased malignancy and significant increase of Tregs that could lead to immunosuppression and evasion of the host immune system.

Inverted urothelial papilloma in a cat

A 12-year-old neutered female cat was referred with clinical signs referable to lower urinary tract disease. Clinical examination revealed a tense, painful urinary bladder, and proximal urethral thickening. Endoscopic studies showed a pedunculated mass with polypoid projections. Multiple full-thickness mucosal biopsies were obtained, and the mass was almost completely excised. The neoplasm was confined to the mucosa and consisted of epithelial cells arranged in anastomosing trabeculae and nests, growing downward into the lamina propria. Neoplastic cells showed minimal atypia and low mitotic activity. Histological findings were consistent with inverted urothelial papilloma. Feline papillomavirus DNA was not amplified from biopsies. One year later, the cat had no urological signs, and urinary bladder was normal at ultrasound. To the authors' knowledge, this is the first report of a case of inverted urothelial papilloma in a cat and is a differential diagnosis for low-grade urothelial carcinoma and other lesions with inverted growth pattern.

Pathological Features and Molecular Phenotype of MMTV Like-Positive Feline Mammary Carcinomas

Simple Summary

Mouse mammary tumour virus-like (MMTV-like) is suspected to be involved in human breast cancer and feline mammary carcinomas (FMCs). We previously reported the identification of MMTV-like sequences and viral protein in six of 78 FMCs collected in Tuscany, Italy. To corroborate this finding, FMCs samples collected from a different geographic area were investigated. MMTV-like sequences and p14 protein were identified in three of 24 FMCs collected at the University of Bologna, one tubular carcinoma, one tubulopapillary carcinoma and one ductal carcinoma. All the examined FMCs from Pisa and Bologna were submitted to immunohistochemistry for molecular phenotype characterization. Of the nine positive FMCs, six were basal-like and three luminal-like. This study highlights the presence of MMTV-like sequences and protein in FMCs of different geographic areas. The characterization of molecular phenotype could contribute to understand the possible role of MMTV-like virus in FMC biological behaviour.

Abstract

In the last few years MMTV-like nucleotide sequences were detected in some feline and canine mammary tumours. Due to the confirmed role of cats in the epidemiology of the MMTV-like virus, the aim of this study was to investigate the main pathological features of positive feline mammary carcinomas (FMCs). Twenty-four FMCs were collected at the University of Bologna, submitted to laser microdissection and analysed by nested fluorescence-PCR using primer sets specific for MMTV env sequence. For immunohistochemistry, an antibody against MMTV protein 14 (p14) was used. MMTV-like sequences were detected in three out of 24 FMCs (12.5%), one tubular carcinoma, one tubulopapillary carcinoma and one ductal carcinoma. All PCR-positive tumours were also positive for p14. Multiple nucleotide alignment has shown similarity to MMTV ranging from 98% to 100%. All the 102 examined FMCs were submitted to immunohistochemistry for molecular phenotyping. Of the nine MMTV-like positive FMCs, six were basal-like and three luminal-like. Our results demonstrate MMTV-like sequences and protein in FMCs of different geographic areas. Molecular phenotyping could contribute to understand the possible role of MMTV-like virus in FMC tumor biology.

Pathological Findings of Canine Idiopathic Pericarditis and Pericardial Mesotheliomas: Correlation with Clinical and Survival Data

Idiopathic pericarditis (IP) and pericardial mesothelioma (PM) are causes of pericardial effusion in dogs. Pericardiectomy can be a definitive treatment in the case of idiopathic pericardial effusion or a short-term intervention for mesothelioma. The aim of the present study was to investigate which histopathologic parameters are correlated with clinical outcomes in a cohort of dogs that underwent pericardiectomy. The histopathological findings of 22 IPs and 5 PMs were compared with clinical and survival data and the immunohistochemical characterization of immune cells (CD3, CD79α, Iba1). In IP, the mesothelium was lost in 20 cases, reactive in 9, atypical in 3, and mesothelial papillary hyperplasia (MPH) was observed in 4 cases. Numerous macrophages were found in both IPs and PMs especially at the superficial layer of the pericardium. T lymphocytes were observed in mild to moderate numbers and were more numerous than B lymphocytes in both IPs and PMs. MPH was correlated with the quantity of lymphoplasmacytic infiltrate in the superficial layer, inversely related to the thickness of the pericardium, and associated with a longer overall survival. Pericardial fibrosis was present in 19 out of 22 IPs and in all mesotheliomas and was correlated with increased time from initial presentation and pericardiectomy and lymphoplasmacytic infiltrate in the deep zone. Pericardial thickness was correlated with the amount of lymphoplasmacytic and macrophagic infiltrate in the deep zone. Mesothelioma was associated with an increased number of pericardiocentesis procedures before pericardiectomy and with the presence of macrophages in the superficial pericardial layer, edema, fibrin, and hemorrhage. Disease-free interval and overall survival were significantly shorter in patients with mesothelioma compared with IP.

Fibroblast-associated protein-α expression and BPV nucleic acid distribution in equine sarcoids

Sarcoids are the most common cutaneous tumor of equids and are caused by bovine papillomavirus (BPV). Different clinical subtypes of sarcoids are well characterized clinically but not histologically, and it is not known whether viral activity influences the clinical or histological appearance of the tumors. The aim of this study was to verify whether the development of different clinical types of sarcoids or the presence of certain histological features were associated with BPV distribution within the tumor. The presence of BPV was assessed by polymerase chain reaction (PCR) and visualized in histological sections by chromogenic in situ hybridization (CISH) in 74 equine sarcoids. Furthermore, to better characterize the molecular features of neoplastic cells, immunohistochemistry for S100, smooth muscle actin-α (αSMA), and fibroblast-associated protein-α (FAPα) was performed. The presence of BPV was confirmed in all tissues examined by either or both PCR and CISH (72/74, 97% each). Of 70/74 CISH-positive cases, signal distribution appeared as either diffuse (61/70, 87%) or subepithelial (9/70, 13%); the latter was more frequently observed in the verrucous subtype. However, no statistically significant association was found between clinical subtypes and specific histological features or hybridization pattern. Moreover, CISH signal for BPV was not detected in the epidermis overlying sarcoids nor in the tissue surrounding the neoplasms. By immunohistochemistry, αSMA confirmed the myofibroblastic differentiation of neoplastic cells in 28/74 (38%) sarcoids. Using tissue microarrays, FAPα labelling was observed in neoplastic fibroblasts of all sarcoids, suggesting this marker as a potential candidate for the immunohistochemical diagnosis of sarcoids.

Primary diaphragmatic undifferentiated pleomorphic sarcoma in a cat

Case summary

A 5-year-old neutered female domestic shorthair cat was referred for acute onset of dyspnoea. Thoracic radiographs performed by the referring veterinarian revealed the presence of pleural effusion. Upon presentation, the cat was dyspnoeic, and cardiopulmonary auscultation revealed muffled heart sounds and bilaterally increased bronchovesicular sounds. Radiographic study of the thorax revealed bilateral pleural effusion and a soft tissue opacity in the dorsocaudal region of the left hemithorax. A whole-body contrast-enhanced CT scan identified a soft tissue mass arising from the left diaphragmatic crus. Transthoracic ultrasound-guided fine-needle aspiration (FNA) of the mass was performed and the result was consistent with a malignant mesenchymal neoplasia, showing giant cells. Cytoreductive surgery was performed and the histopathology diagnosis of undifferentiated pleomorphic sarcoma was made. Adjuvant chemotherapy was then offered. Ten days after surgery pleural effusion recurred. Thoracic echography revealed the presence of a diaphragmatic thickening in the area of surgical resection. FNA of the thickening was consistent with mesenchymal neoplasia. Even when chemotherapy and supportive treatment with pain relief was instituted, the clinical condition of the cat worsened within a few days and it was euthanased 1 month after surgery.

Relevance and novel information

Primary diaphragmatic tumours (PDTs) have been rarely reported in human and in veterinary medicine, where only three cases have been described in the dog. To our knowledge, this is the first report to describe a PDT, specifically an undifferentiated pleomorphic sarcoma, in a cat.

Epidemiologic case investigation on the zoonotic transmission of Staphylococcus aureus infection from goat to veterinarians

Staphylococcus aureus infection led to a case of goat abortion, and four veterinarians contracted S. aureus infection from the goat during and after the abortion. Three veterinarians assisted a doe during the dystocic delivery of a dead foetus. Seventy-two hours after the dystocia, which ended with the goat's death, the veterinarians who assisted during the kidding and the veterinarian who performed the necropsy showed the presence of multiple, isolated, painful pustules 1-5 mm in diameter located along their forearms and knees. S. aureus was isolated from the pustules of the veterinarians, the placenta and uterus of the goat, the organs (brain, thymus gland, abomasum, liver and spleen) of the foetus, the scrotum and eye swabs of the buck, and mammary pustules of another goat from the same herd. Histological analysis revealed purulent metritis and inflammation of the placental cotyledons. Additional investigations eliminated the chances of other infections. S. aureus isolates recovered from the veterinarians, goats, foetus and buck were sensitive to the tested anti-microbials and did not encode staphylococcal enterotoxin genes (sea, ser, sep, see, seg and sei). The isolates were closely related, as indicated by the results of Fourier-transform infrared spectroscopy and comparative whole-genome sequencing analysis. The results of this study clearly support the hypothesis that an episode of professional zoonosis was caused by S. aureus infection during the abortion and also highlight the need for bacterial subtyping in epidemiological surveys.

High Intrinsic Expression of P-glycoprotein and Breast Cancer Resistance Protein in Canine Mammary Carcinomas Regardless of Immunophenotype and Outcome

P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) are major actors in multidrug resistance (MDR) phenomenon in both human and canine mammary carcinomas (CMCs). The aim of this study was to investigate an association between the intrinsic expression of P-gp and BCRP compared to the immunophenotypes and outcome in CMCs. Fifty CMCs were evaluated at immunohistochemistry (IHC) for P-gp, BCRP, Estrogen receptor alpha (ER), Progesterone receptors (PR), Human Epidermal Growth Factor Receptor type 2 (HER2), basal cytokeratins 5/6 (CK5/6), Epidermal Growth Factor Receptor 1 (EGFR), and Ki67 proliferation index. P-gp and BCRP positive cases were, respectively, 52% and 74.5%, with a significantly higher expression of BCRP than P-gp. Five immunophenotypes were defined in 37 out of 50 CMCs: 9 (24.3%) Luminal A, 5 (13.5%) Luminal B, 9 (24.3%) HER2 overexpressing, 9 (24.3%) Triple-negative basal-like, and 5 (13.5%) Triple-negative non-basal-like. In all CMCs at least one marker was expressed. Follow-up data were available for 25 animals. The average cancer-specific survival was 739 ± 444 days. A number of CMCs bear a high expression of P-gp and BCRP but no significant association was found between their expression and the immunophenotypes, Ki67 index, the histological grade, and tumor-related death.

HER2 Overexpression and Amplification in Feline Pulmonary Carcinoma

HER2 is overexpressed, amplified, and mutated in a subset of human lung cancer. The aim of this study was to investigate HER2 protein overexpression and gene amplification in feline pulmonary carcinomas. Thirteen pulmonary carcinomas were selected and TTF-1 and HER2 expression was evaluated by immunohistochemistry. Fluorescence in situ hybridization (FISH) was performed with a HER2 probe and a BAC probe for the feline chromosome E1p1.12-p1.11 region. Twelve adenocarcinomas and 1 squamous cell carcinoma were diagnosed. TTF-1 was positive in 7 carcinomas (58%). HER2 was overexpressed in 2 (15%), equivocal in 5 (38%), and negative in 6 cases (46%). FISH analysis of HER2 was indeterminate in 2 cases. Three pulmonary carcinomas (27%) had HER2 amplification and 8 cases were not amplified (73%). The significant correlation between HER2 protein overexpression and gene amplification are promising preliminary data, but study of additional cases is needed to confirm HER2 as a target for possible innovative treatments.

Doxorubicin treatment modulates chemoresistance and affects the cell cycle in two canine mammary tumour cell lines

BACKGROUND

Doxorubicin (DOX) is widely used in both human and veterinary oncology although the onset of multidrug resistance (MDR) in neoplastic cells often leads to chemotherapy failure. Better understanding of the cellular mechanisms that circumvent chemotherapy efficacy is paramount. The aim of this study was to investigate the response of two canine mammary tumour cell lines, CIPp from a primary tumour and CIPm, from its lymph node metastasis, to exposure to EC50(20h) DOX at 12, 24 and 48 h of treatment. We assessed the uptake and subcellular distribution of DOX, the expression and function of P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP), two important MDR mediators. To better understand this phenomenon the effects of DOX on the cell cycle and Ki67 cell proliferation index and the expression of p53 and telomerase reverse transcriptase (TERT) were also evaluated by immunocytochemistry (ICC).

RESULTS

Both cell lines were able to uptake DOX within the nucleus at 3 h treatment while at 48 h DOX was absent from the intracellular compartment (assessed by fluorescence microscope) in all the surviving cells. CIPm, originated from the metastatic tumour, were more efficient in extruding P-gp substrates. By ICC and qRT-PCR an overall increase in both P-gp and BCRP were observed at 48 h of EC50(20h) DOX treatment in both cell lines and were associated with a striking increase in the percentage of p53 and TERT expressing cells by ICC. The cell proliferation fraction was decreased at 48 h in both cell lines and cell cycle analysis showed a DOX-induced arrest in the S phase for CIPp, while CIPm had an increase in cellular death without arrest. Both cells lines were therefore composed by a fraction of cells sensible to DOX that underwent apoptosis/necrosis.

CONCLUSIONS

DOX administration results in interlinked modifications in the cellular population including a substantial effect on the cell cycle, in particular arrest in the S phase for CIPp and the selection of a subpopulation of neoplastic cells bearing MDR phenotype characterized by P-gp and BCRP expression, TERT activation, p53 accumulation and decrease in the proliferating fraction. Important information is given for understanding the dynamic and mechanisms of the onset of drug resistance in a neoplastic cell population.

p53, ER, and Ki67 Expression in Canine Mammary Carcinomas and Correlation With Pathological Variables and Prognosis

Using immunohistochemistry, 170 canine mammary carcinomas were evaluated for p53, ER (estrogen receptor), and Ki67. Of the 170 tumors, 89 were grade I (52.3%), 36 were grade II (21.2%), and 45 were grade III (26.4%). Eight cases (0.5%) were positive for p53 and 69/170 cases (40.5%) were positive for ER. Ki67 values were 24 ± 18% (mean ± SD). Using a cutoff value of 33.3% Ki67-positive neoplastic nuclei, 38/159 (23.8%) were classified as high proliferative and 121/159 (76.2%) as low proliferative. p53-positive cases had significantly higher Ki67 expression and higher histological grade. ER expression was not correlated with p53 expression but was significantly related to low Ki67 values and low histological grade. Moreover, ER-positive cases had significantly longer survival compared to ER-negative tumors, and ER expression had better correlation with tumor-related survival than histological grade. In summary, p53 accumulated in a small subset of canine mammary tumors and was associated with higher proliferative activity and higher histological grade. ER expression was confirmed as a differentiation marker associated with more favorable prognosis and biological behavior. The combined use of these 3 markers could be used in addition to histological grade to predict the biological behavior of canine mammary carcinomas.

Canine Mammary Carcinoma With Vacuolated Cytoplasm: Glycogen-Rich Carcinoma, a Histological Type Distinct From Lipid-Rich Carcinoma

Lipid-rich carcinoma is a rare histotype of canine mammary tumors with cytoplasmic vacuolation. In humans, glycogen-rich carcinoma, secretory carcinoma, and myoepithelial neoplasms are included in the differential diagnosis for lipid-rich carcinoma. The aim of the study was to investigate the existence of histotypes other than lipid-rich in canine mammary carcinomas with vacuolated cytoplasm using a diagnostic algorithm based on histopathology, histochemistry, immunohistochemistry, and ultrastructure and to evaluate the molecular phenotype of these neoplasms. Ten mammary carcinomas were collected, histologically reviewed, and subjected to histochemistry (PAS, PAS with diastase, Alcian blue, Sudan III [1 case], and Congo red [1 case]); immunohistochemistry for CK19, CK5/6, CK14, p63, calponin, vimentin, ER, PR, and HER2; and transmission electron microscopy (TEM). Cytokeratin immunolabeling demonstrated the epithelial origin of all tumors. Sudan III and TEM confirmed the diagnosis of lipid-rich carcinoma in 8 tumors (one amyloid-producing). One tumor was reclassified as a glycogen-rich carcinoma based on PAS reactivity that was diastase-labile, and a second tumor was reclassified as a carcinoma-and-malignant myoepithelioma based on the differentiation markers. Lipid-rich carcinomas were basal-like (5/8), null-type (2/8), and luminal A phenotype (1/8). The glycogen-rich carcinoma was basal-like, while the carcinoma-and-malignant myoepithelioma was luminal A. Vacuolated morphology of neoplastic cells in canine mammary carcinoma can indicate either a neoplasm of luminal epithelial origin with cytoplasmic lipid or glycogen, or vacuolated neoplastic suprabasal myoepithelial cells. Glycogen-rich carcinoma is a novel histological type that should be considered in the differential diagnosis for canine mammary carcinomas with vacuolated cytoplasm.

X-Linked Duchenne-Type Muscular Dystrophy in Jack Russell Terrier Associated with a Partial Deletion of the Canine DMD Gene

A 9-month old male Jack Russell Terrier started showing paraparesis of the hindlimbs after a walk. Hospitalized, the dog went into cardiac arrest, and later died. Necroscopic examination revealed a severe thickness of the diaphragm, esophagus, and base of the tongue, leading to the diagnosis of muscular dystrophy. The histology confirmed the marked size variation, regeneration, and fibrosis replacement of the skeletal muscle fibers. Immunohistochemistry demonstrated the absence of dystrophin confirming the diagnosis. Transmission electron microscopy showed disarrangement of skeletal muscle fibers. Finally, whole-genome sequencing identified a ~368kb deletion spanning 19 exons of the canine dystrophin (DMD) gene. This pathogenic loss-of-function variant most likely explains the observed disease phenotype. The X-chromosomal variant was absent in seven controls of the same breed. Most likely, this partial deletion of the DMD gene was either transmitted on the maternal path within the family of the affected dog or arose de novo. This study revealed a spontaneous partial deletion in DMD gene in a Jack Russell Terrier showing a Duchenne-type muscular dystrophy due to non-functional dystrophin.

Short-term surgical outcomes and histomorphological evaluation of thermal injury following palatoplasty performed with diode laser or air plasma device in dogs with brachycephalic airway obstructive syndrome

Brachycephalic obstructive airway syndrome (BOAS) is a common disorder presenting enlarged soft palate, stenotic nares and abnormal turbinate growth. Surgical correction of BOAS abnormalities with caudal palatoplasty is an elective therapy. This prospective study aimed to compare the effect of an air plasma device and diode laser in dogs undergoing palatoplasty. Outcome measures were as follows: (1) intra-operative and immediate post-operative complications; (2) evaluation of thermal injury in histological tissue sections of the excised soft palate. Twenty dogs with enlarged soft palates underwent palatoplasty, using an air plasma device (n=10) and diode laser (n=10). Soft palate specimens underwent masked histopathological analysis to assess post-operative thermal injury. In this pilot study, no differences were observed in surgical times; all dogs were discharged 24h after surgery and had stable respiration. In the air plasma group, post-operative bleeding occurred in two cases and revision surgery was performed. No difference in thermal injury was observed using the two devices (P>0.05). The air-plasma device was a viable surgical option for palatoplasty in dogs with BOAS.

P-Glycoprotein and Breast Cancer Resistance Protein in Canine Inflammatory and Noninflammatory Grade III Mammary Carcinomas

P-glycoprotein (P-gp/ABCB1) and breast cancer resistance protein (BCRP/ABCG2) expression are frequently related to multidrug resistance (MDR) in neoplastic cells. Canine inflammatory and grade III noninflammatory mammary carcinomas (IMC and non-IMC) are aggressive tumors that could benefit from chemotherapy. This study describes the immunohistochemical detection of P-gp and BCRP in 20 IMCs and 18 non-IMCs from dogs that had not received chemotherapy. Our aim was to determine if P-gp and BCRP expression was related to the "inflammatory" phenotype, to establish a basis for future studies analyzing the response to chemotherapy in dogs with highly malignant mammary cancer. Immunolabeling was primarily membranous for P-gp with a more intense labeling in emboli, and immunolabeling was membranous and cytoplasmic for BCRP. P-gp was expressed in 17 of 20 (85%) IMCs compared to 7 of 18 (39%) non-IMCs (P = 0.006). BCRP was expressed within emboli in 15 of 19 (79%) emboli in IMC, 12 of 15 (80%) primary IMCs, and 12 of 18 (67%) non-IMCs, without statistically significant differences (P > .05). All IMCs and 67% of non-IMCs expressed at least 1 of the 2 transporters, and 63% (12/19) of IMCs and 39% (7/18) of non-IMCs expressed both P-gp and BCRP. P-gp and BCRP evaluation might help select patients for chemotherapy. P-gp, expressed in a significantly higher percentage of IMCs vs non-IMCs, might play a specific role in the chemoresistance of IMC.

Treatment of Severe Gynecomastia After Massive Weight Loss: Analysis of Long-Term Outcomes Measured with the Italian Version of the BODY-Q

INTRODUCTION

The objectives of this study are: (1) comparison of long-term outcomes after correction of severe gynecomastia using different techniques; (2) apply the Italian version of the BODY-Q; (3) present the role of intercostal perforator flap (ICAP) after massive weight loss for correction of severe gynecomastia.

MATERIALS AND METHODS

Between January 2008 and March 2016, we performed surgical correction of bilateral severe gynecomastia in 80 men (160 breasts) following massive weight loss. Patients answered the Italian version of BODY-Q postoperative module. All patients had experienced substantial weight loss (> 30 kg), presented with bilateral severe tissue ptosis of the breast, follow-up of almost 2 years and had a good understanding of the Italian language, and signed consents were included in the study. The sample was studied about age, BMI, comorbidity, bariatric surgical procedure, follow-up, type of post-bariatric surgical procedure, complications and secondary procedures.

RESULTS

We performed 487 severe gynecomastia corrections from 2008 to 2016; 80 patients adhered to the inclusion criteria and formed our study group. This cross-sectional study compared three cohorts: 52 access using a circumareolar scar, 18 with an inframammary fold scar, 10 with an inframammary fold scar using intercostal perforator flaps. There were 16 secondary procedures in group one, 2 in group two and 1 in group three. We compared the secondary procedures of group 1 with the other groups, and we obtained a significant difference with a P = 0.04. The mean patient age was 36.5 years, and the average body mass index was 27.5 kg/m² at the time of surgical correction of gynecomastia. From the BODY-Q analysis, the group of patients undergoing adenomammectomy with inframammary fold scar using intercostal perforator flaps has achieved significantly better results regarding the satisfaction with chest, psychosocial function, satisfaction with outcome and better body image.

CONCLUSIONS

This is the first study that used the BODY-Q to analyze the correction of severe gynecomastia following massive weight loss with long-term results. The use of this patient-reported outcome measure underlined that the intercostal artery perforator flap, used in the correction of severe gynecomastia following massive weight loss, is a safe and effective technique with good outcomes and high patient satisfaction.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

HER2 Amplification Status in Feline Mammary Carcinoma: A Tissue Microarray-Fluorescence In Situ Hydridization-Based Study

Human epidermal growth factor receptor 2 (HER2) is a tyrosine kinase receptor overexpressed in a subset of breast cancer due to HER2 gene amplification. HER2 protein is expressed in feline mammary carcinomas, but little is known about its cytogenetic alterations. The aim of this study was to evaluate HER2 gene amplification status and its correlation with HER2 protein expression in feline mammary carcinomas. Feline mammary carcinomas were retrospectively selected and immunohistochemically (IHC) evaluated for HER2 protein expression. All the HER2 IHC-positive (3+) and equivocal (2+) cases and a subset of negative cases (0/1+) were selected for fluorescence in situ hybridization (FISH). Dual-core tissue microarrays were prepared for FISH. IHC and FISH were evaluated according to the 2013 American Society of Clinical Oncology/College of American Pathologists guidelines. The study included 107 feline mammary carcinomas from 88 queens. HER2 protein expression was positive (3+) in 7 cases (6.5%), equivocal (2+) in 48 cases (45%), and negative (0/1+) in 52 cases (48.5%). HER2 status was indeterminate in 8 feline mammary carcinomas (12%), amplified in 3 (4%), equivocal in 4 (6%), and nonamplified in 53 (78%). HER2 gene amplification and protein expression were significantly positively correlated ( R = 0.283; P < .0001). HER2 gene is amplified in a subset of feline mammary carcinomas despite the HER2 positive or equivocal protein expression, but it remains to be determined if the HER2 amplification is a gene alteration that drives mammary tumor carcinogenesis or only a bystander passenger mutation.

Wearable Wireless Tyrosinase Bandage and Microneedle Sensors: Toward Melanoma Screening

Wearable bendable bandage-based sensor and a minimally invasive microneedle biosensor are described toward rapid screening of skin melanoma. These wearable electrochemical sensors are capable of detecting the presence of the tyrosinase (TYR) enzyme cancer biomarker in the presence of its catechol substrate, immobilized on the transducer surface. In the presence of the surface TYR biomarker, the immobilized catechol is rapidly converted to benzoquinone that is detected amperometrically, with a current signal proportional to the TYR level. The flexible epidermal bandage sensor relies on printing stress-enduring inks which display good resiliency against mechanical deformations, whereas the hollow microneedle device is filled with catechol-coated carbon paste for assessing tissue TYR levels. The bandage sensor can thus be used directly on the skin whereas microneedle device can reach melanoma tissues under the skin. Both wearable sensors are interfaced to an ultralight flexible electronic board, which transmits data wirelessly to a mobile device. The analytical performance of the resulting bandage and microneedle sensing systems are evaluated using TYR-containing agarose phantom gel and porcine skin. The new integrated conformal portable sensing platforms hold considerable promise for decentralized melanoma screening, and can be extended to the screening of other key biomarkers in skin moles.

Glomeruloid Microvascular Proliferation, Desmoplasia, and High Proliferative Index as Potential Indicators of High Grade Canine Choroid Plexus Tumors

Choroid plexus tumors (CPT) are intraventricular neoplasms accounting for 10% of all primary central nervous system tumors in dogs. They are frequently classified according to the human WHO classification into choroid plexus papilloma (CPP, grade I), atypical CPP (aCPP, grade II), and choroid plexus carcinoma (CPC, grade III). Histological features observed in canine CPT such as increased vascular density (IVD) and glomeruloid microvascular proliferation (GMVP) are not part of the WHO classification. This multi-centric study aimed to investigate tumor-associated vascular hyperplasia in dogs by determining the prevalence of GMVP and IVD in 52 canine CPT and their association with tumor grade. In addition, the expression of angiogenic factors was assessed by immunohistochemistry in 25 tumors to investigate the pathogenesis of tumor-associated vascular hyperplasia. Based on the classical histological hallmarks, this study of 52 CPT identified 22 (42%) CPP (grade I) and 30 of (58%) CPC (grade III). GMVP was more prevalent in CPC (13/30; 43%) than CPP (1/22; 4%), whereas IVD occurred to a similar extent in CPP and CPC. Desmoplasia was more common in CPC (19/30; 63%) than CPP (2/22; 9%), and similarly, the proliferative index (PI) of neoplastic epithelium was significantly higher in CPC (5.14%) than CPP (0.94%). The majority of CPT expressed platelet-derived growth factor (PDGF), PDGFRα, PDGFRβ, and vascular endothelial growth factor (VEGF) irrespective of tumor grade or tumor-associated vascular hyperplasia. These results suggest that tumor-associated GMVP, desmoplasia, and PI may serve as histological indicators of malignancy in CPT.

Management of contralateral breast following mastectomy and breast reconstruction using a mirror adjustment with crescent mastopexy technique

INTRODUCTION

Heterologous breast reconstruction after mastectomy sometimes requires the management of the contralateral breast to achieve symmetric long lasting aesthetic results. Some techniques could be used for the symmetrization of contralateral breast with or without implants as breast augmentation, reduction mammoplasty, mastopexy, with T inverted, J, vertical, periareolar, semi-circular, or axillary scars. The aim of this study is to present the use of crescent mastopexy technique with implants in contralateral adjustment following monolateral breast reconstruction compared with a control group in which patients underwent other contralateral procedures. We used BREAST-Q to evaluate breast perception and patient's satisfaction and surgeon-rated aesthetic outcomes were measured using the Kroll evaluation (a global and itemized aesthetic tool).

MATERIALS AND METHODS

A retrospective study was designed. We enrolled in the study 55 patients who had undergone breast reconstruction with implants and contralateral breast symmetrization procedure at our hospital between 2010 and 2016, and they answered to BREAST-Q postoperative module after almost 1 year from breast reconstruction. The study population consisted of 2 groups of women: patient underwent contralateral adjustment with crescent mastopexy and augmentation and patients underwent other contralateral procedures. Statistical analysis was performed using descriptive and summary statistics to identify a central tendency between the two groups, we applied Fisher's exact test to the results to obtain answers 1 year after the last procedure for the two groups.

RESULTS

This cross-sectional study compared two cohorts in which 55 women underwent monolateral mastectomy and breast reconstruction with contralateral adjustment, 15 of these underwent contralateral crescent mastopexy with augmentation, and 40 (control group) underwent contralateral breast adjustment with other mastopexy and augmentation technique (27 patients underwent T inverted mastopexy, 2 J mastopexy, 6 vertical scar mastopexy, 5 periareolar mastopexy). Nineteen patients suffered of co-morbidities (smoking, autoimmune disease, cardiological, neurological, and dismetabolic). All patients answered the postoperative BREAST-Q reconstruction module almost 1 year from last surgical procedure.

CONCLUSIONS

In patients with a pseudoptosis or mild ptosis of the contralateral breast, crescent mastopexy could be a valid procedure with minimal scars, better symmetry, and global cosmetic results than other procedures. This is the first study which compares crescent mastopexy with augmentation with other mastopexy procedures. Level III: evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than one center or research group.

LEVEL (III)

Evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than one center or research group.

Immunohistochemical Expression of P-glycoprotein and Breast Cancer Resistance Protein in Canine Mammary Hyperplasia, Neoplasia and Supporting Stroma

The ability of a tumour to become simultaneously resistant to different drugs is known as multidrug resistance and is often due to the expression of ATP-dependent binding cassette transporters (ABC-transporters) such as P-glycoprotein (PGP) and breast cancer resistance protein (BCRP). In this study, the expression of PGP and BCRP was determined in the components of hyperplastic and neoplastic canine mammary glands, including the supporting stroma. The variation of expression of these molecules in carcinomas was evaluated between lesions of different histological stage and grade of malignancy. Samples included 47 hyperplastic tissues and 10 benign and 46 malignant neoplasms. Tumours were classified into histological subtype, histological stage and grade. Immunohistochemical evaluation of PGP and BCRP expression showed that both markers are potentially expressed by epithelial cells, myoepithelial cells in complex tumours and mesenchymal cells in mixed tumours, but expression of both proteins was significantly higher in malignant epithelial cells versus hyperplastic epithelium or the epithelium of benign tumours. BCRP showed significantly higher expression in epithelial cells of simple carcinomas versus those of complex and mixed carcinomas. Grade II and III carcinomas had higher epithelial PGP expression than grade I tumours. The positivity of stromal fibroblasts was higher in histological stage II versus I carcinomas, and in histological grade II versus I carcinomas. Malignant and invasive tumours were more likely to express PGP and/or BCRP in luminal and stromal components and evaluation of these markers could provide valuable information for the identification of tumours characterized by an aggressive and chemoresistant phenotype.

Mammary Mucinous Carcinoma in the Cat

Mucinous carcinoma of the mammary gland is a rare tumor characterized by excessive mucin production. In human and canine pathology, the diagnosis of mucinous carcinoma is based on the demonstration of an epithelial phenotype of mucus-producing cells and periodic acid-Schiff (PAS)-diastase positivity of the mucin. The histologic and immunohistologic characteristics of feline mucinous mammary carcinoma were examined. Of 656 cases of feline mammary neoplasms and dysplasias, 3.2% were found to be mucin-producing tumors. Cytokeratin 19 (16 cases positive, 4 heterogenous, and 1 negative) and vimentin (15 cases positive, 2 heterogenous, and 4 negative) expression were examined, and the mucin produced was alcian blue positive. PAS-diastase staining was variable (38.1%). Based on these findings, mucinous mammary carcinoma in the cat varies significantly from the human and canine varieties and alcian blue is the prominent stain in the diagnosis of feline mucinous carcinoma.

E-Cadherin Immunoreactivity in Canine Mammary Tumors

The reduction or loss of E-cadherin (E-cad), a calcium-dependent epithelial cell adhesion molecule, has been associated with tumor dedifferentiation and invasiveness. The immunohistochemical pattern of E-cad expression was evaluated in formalin-fixed and paraffin-embedded sections of 6 normal mammary glands, 3 dysplasias, 12 benign tumors (8 benign mixed tumors, 4 adenomas), and 60 malignant tumors (12 stage 0, 29 stage I, 19 stage II) of the canine mammary gland. E-cadherin expression was classified as membranous, when on cell–cell boundaries, or as cytoplasmic, when in the form of a diffuse cytoplasmic staining. In addition, the percentage of E-cad–positive epithelial neoplastic cells was graded by a semiquantitative method, categorizing cases into a reduced (or -) type group, when showing less than 25% positivity, a reduced (or +/-) type group, when showing 25–75% positivity, and a preserved (or +) type group, when more than 75% positive cells were present. In the normal mammary gland, E-cad expression was evident in epithelial luminal cells. A stronger positivity was revealed in ductular than in alveolar luminal cells. The myoepithelial cells showed inconsistent, weak cytoplasmic positivity in the normal gland as well as in mammary tumors. In normal glands and benign and malignant noninvasive tumors, E-cad expression was mainly membranous and preserved in most of the epithelial cells. In stage I tumors, both membranous (38%) and cytoplasmic (62%) positivity were well represented, as well as preserved type (55%) and reduced type (45%) tumors. All stage II malignant tumors showed the highest frequency of cytoplasmic positivity (79%) and reduced type (62%) tumors.

Evaluation of Telomerase in Canine Mammary Tissues by Immunohistochemical Analysis and a Polymerase Chain Reaction-Based Enzyme-Linked Immunosorbent Assay

The enzyme telomerase is considered a potential marker for neoplastic tissue and is used as a diagnostic and prognostic tool in clinical medicine and therapeutics. For this reason, the possible role of telomerase activation in the process of malignant transformation is currently the subject of intense research efforts. The focus of the study reported here was to detect telomerase in 37 canine mammary samples, by comparing two methods: immunohistochemical (IHC) analysis for detecting the catalytic subunit of the enzyme, telomerase reverse transcriptase (TERT), and the telomeric repeat amplification protocol–enzyme-linked immunosorbent assay (TRAP-ELISA), a polymerase chain reaction (PCR)-based technique that uses a colorimetric detection method. Using the TRAP-ELISA, samples were considered positive when they yielded a difference of at least 0.2 absorbance units between the readings at 450 nm versus 690 nm wavelength. On the basis of this criterion, 18 negative and 19 positive cases were obtained. Specific immunohistochemical staining was observed mainly in the nucleoli, to a lesser extent in the nuclei, and rarely in the cytoplasm of epithelial cells. A sample was considered positive when at least 10% of the epithelial cells had specific staining. The Pearson correlation between the TRAP-ELISA and IHC results was significant only when IHC nucleolar ( r = 0.53, P < 0.01) or nuclear ( r = 0.36, P < 0.05) staining or their combination ( r = 0.58, P < 0.01) was considered. Thus, IHC staining of nucleoli and nuclei can be considered as an alternative method to the TRAP-ELISA. The detection of telomerase in normal mammary gland and fibrocystic mastopathy using both methods does not support the idea that telomerase may be used as a specific marker of mammary neoplasia in dogs.

Histological Classification and Immunohistochemical Evaluation of MDM2 and CDK4 Expression in Canine Liposarcoma

Canine liposarcoma is an uncommon soft tissue sarcoma usually arising in the subcutis. While liposarcoma classification in dogs is based solely on histology, in humans it depends on the detection of genetic abnormalities that can lead to specific protein overexpression. This study is an immunohistochemical evaluation of MDM2 and CDK4 expression in canine liposarcoma designed to assess the correlation of these proteins with histologic type, grade, mitotic index and Ki67 labeling index and evaluate their utility in improving tumor classification. Fifty-three liposarcomas were retrospectively collected: 24 were well differentiated liposarcomas (WDL), 16 of which expressed MDM2 and 21 CDK4; 7 were myxoid liposarcomas (ML), 1 of which expressed MDM2 and 5 expressed CDK4; 18 were pleomorphic liposarcomas (PL), all were MDM2 negative and 12 expressed CDK4. Four tumors were morphologically consistent with dedifferentiated liposarcoma (DDL) a subtype described only in humans: 3 expressed MDM2 and 4 expressed CDK4. MDM2 expression correlated with histotype (highly expressed in WDL and DDL) and grade (highly expressed in grade 1 tumors). Histotype correlated with the Ki67 labeling index (lowest in WDL and highest in DDL). A revised classification, considering MDM2 expression, allowed 8 WDL to be reclassified as PL and correlated significantly with mitotic and Ki67 labeling index (both significantly lower in WDL and progressively higher in ML and DDL). These results partially parallel data reported for human liposarcomas, suggesting that WDL and DDL are distinct neoplastic entities characterized by MDM2 expression, which may represent a useful diagnostic and potentially prognostic marker for canine liposarcoma.