Prognostic significance of immunohistochemical markers and histological classification in malignant canine mammary tumours

Risk factor analysis and clinicopathological characteristics of female dogs with mammary tumours from a single-center retrospective study in Poland

This is a comprehensive retrospective study to characterize female dogs with canine mammary tumors (CMTs) using a dataset retrieved from the archives of the Division of Animal Pathology, Institute of Veterinary Medicine in Warsaw, and to identify prognostic factors. Clinical and histopathological data of 1447 dogs with CMTs were included. Malignant tumours were found in 83.3% (n = 1206), benign tumours in 11.7% (n = 169), and non-neoplastic lesions in 5.0% (n = 72) of dogs. Dogs most often had grade II carcinomas (38.2%, 215/562) of a single histological subtype (88.5%, 1281/1447), mostly simple carcinoma (35.3%, 510/1447). Dogs with a median age of 10 years significantly often had larger (≥ 3 cm) and malignant CMTs, whereas intact females had smaller tumours (median size 2.0 cm). However, the threshold value for the age of the dog in the differentiation of malignant and non-neoplastic/benign masses could not be determined. Most females were hormonally active (76.4%, 372/487). Hormonally active dogs significantly more often had multiple tumours. Multiple tumours were significantly smaller (median 2.5 cm) than single ones. Among pedigree dogs, small-breed dogs were mostly recorded (43%, 428/1006). Twelve breeds had an increased risk of CMTs, regardless of tumour behaviour, compared with the theoretical distribution of pedigree dogs in Poland. Four breeds were often affected only by malignant and other four breeds only by non-neoplastic/benign CMT. Large-breed dogs were significantly younger and affected by larger CMT (median 4 cm) compared with small- and medium-breed dogs. Ninety dogs with a malignant CMT and complete records were included in the full analysis of CMT-specific survival (CMT-SS) with a median follow-up time of 20.0 months. We showed that the timing of ovariohysterectomy in relation to mastectomy was significantly associated with grade, CMT-SS, and CMT-related death. We indicated the low diagnostic accuracy of palpation of regional lymph nodes (RLN) in the prediction of their metastatic involvement. By multivariable analysis, dogs with neoplastic emboli, tumour ulceration, and simple or complex carcinoma had a significantly higher risk of local recurrence. Tumour size > 3 cm was as a strong independent predictor of lung metastases. Compared with dogs with an easily separated localized tumour, dogs with a multiple/diffuse malignant CMT pattern had a fivefold higher risk of death. The risk of death was significantly higher in the presence of neoplastic emboli (~ fivefold) and tumour ulceration (~ fourfold). Furthermore, the presence of neoplastic emboli and large tumour size were independent predictors of CMT-related death.

Mammary Glands of Women, Female Dogs and Female Rats: Similarities and Differences to Be Considered in Breast Cancer Research

Breast cancer is one of the most common and well-known types of cancer among women worldwide and is the most frequent neoplasm in intact female dogs. Female dogs are considered attractive models or studying spontaneous breast cancer, whereas female rats are currently the most widely used animal models for breast cancer research in the laboratory context. Both female dogs and female rats have contributed to the advancement of scientific knowledge in this field, and, in a "One Health" approach, they have allowed broad understanding of specific biopathological pathways, influence of environmental factors and screening/discovery of candidate therapies. This review aims to clearly showcase the similarities and differences among woman, female dog and female rat concerning to anatomical, physiological and histological features of the mammary gland and breast/mammary cancer epidemiology, in order to better portray breast tumorigenesis, and to ensure appropriate conclusions and extrapolation of results among species. We also discuss the major aspects that stand out in these species. The mammary glands of female dogs and women share structural similarities, especially with respect to the lactiferous ducts and lymphatic drainage. In contrast, female rats have only one lactiferous duct per nipple. A comprehensive comparison between humans and dogs is given a special focus, as these species share several aspects in terms of breast/mammary cancer epidemiology, such as age of onset, hormonal etiology, risk factors, and the clinical course of the disease. Holistically, it is clear that each species has advantages and limitations that researchers must consider during the development of experimental designs and data analysis.

Canine Mammary Neoplasia Induces Variations in the Peripheral Blood Levels of CD20, CD45RA, and CD99

The idea of using tumour biomarkers as diagnostic tools is progressively increasing. Of these, serum biomarkers are of particular interest, as they can provide rapid results. In the present study, serum samples from 26 bitches diagnosed with mammary tumours, plus 4 healthy bitches, were obtained. The samples were analysed using CD antibody microarrays targeting 90 CD surface markers and 56 cytokines/chemokines. A total of five CD proteins, namely CD20, CD45RA, CD53, CD59, and CD99, were selected and further analysed, utilizing immunoblotting techniques to validate the microarray results. CD45RA showed a significantly lower abundance in the serum samples from the bitches carrying mammary neoplasia in comparison to the healthy animals. Regarding CD99, the serum samples from the neoplastic bitches showed it in a significantly higher abundance than those from the healthy patients. Finally, CD20 showed a significantly higher abundance in bitches carrying a malignant mammary tumour in comparison to healthy patients, but no differential expression between malignant and benign tumours was observed. According to these results, both CD99 and CD45RA are indicators of mammary tumour presence, but without distinguishing between malignant and benign.

Tetramethylpyrazine-Rhein Derivative inhibits the migration of canine inflammatory mammary carcinoma cells by mitochondrial damage-mediated apoptosis and cadherins downregulation

BACKGROUND

Canine inflammatory mammary carcinoma (CIMC) has a high incidence of metastasis, high lethality, and poor prognosis, which needs novel adjuvant agents. Tetramethylpyrazine-Rhein Derivative (TRD) has been shown to have antitumor activity, which is a potential research direction for CIMC.

PURPOSE

This study evaluated the efficacy of TRD on CIMC in vitro and in vivo, and provided possibilities for the application of active compounds in traditional Chinese medicine.

METHODS

In vitro, TRD cytotoxicity was measured with CCK-8. Flow cytometry and transmission electron microscope were used to detect the cell cycle, cell death, and changes in mitochondria. Wound-healing assay, cell invasion assay, and scanning electron microscope were used to evaluate the suppression of cell migration and invasion. Expression changes were detected by RT-qPCR and western blot assay. In vivo, the lung metastasis models were randomly divided into control, low-dose TRD, high-dose TRD, and positive groups. Each group was administered orally once a day for 18 days and took in vivo imaging photos.

RESULTS

The IC₅₀ of TRD in CHMp and MDCK were 42.59 and 79.37 μM, respectively. TRD mediated cell apoptosis by mitochondrial damage and caused S and G₂/M phase arrest by downregulating cyclin B1. Moreover, TRD reduced filopodia and inhibited cell migration by downregulating cadherins. In CIMC lung metastasis models, TRD could effectively inhibit tumor growth (P < 0.001) in the lungs without significant toxicity.

CONCLUSION

TRD showed potential activity to inhibit CIMC lung metastasis with multi-target and low toxicity.

Associations Between Dog Breed and Clinical Features of Mammary Epithelial Neoplasia in Bitches: an Epidemiological Study of Submissions to a Single Diagnostic Pathology Centre Between 2008-2021

Mammary cancer is one of the most common neoplasms of dogs, primarily bitches. While studies have been carried out identifying differing risk of mammary neoplasia in different dog breeds, few studies have reported associations between dog breeds and clinical features such as number of neoplastic lesions found in an individual case or the likelihood of lesions being benign or malignant. Such epidemiological studies are essential as a foundation for exploring potential genetic drivers of mammary tumour behaviour. Here, we have examined associations between breed, age and neuter status and the odds of a diagnosis of a mammary epithelial-origin neoplastic lesion (as opposed to any other histopathological diagnosis from a biopsied lesion) as well as the odds of a bitch presenting with either a single mammary lesion or multiple lesions, and the odds that those lesions are benign or malignant. The study population consisted of 129,258 samples from bitches, including 13,401 mammary epithelial neoplasms, submitted for histological assessment to a single histopathology laboratory between 2008 and 2021.In multivariable analysis, breed, age and neuter status were all significantly associated with the odds of a diagnosis of a mammary epithelial-origin neoplastic lesion. Smaller breeds were more likely to receive such a diagnosis. In cases diagnosed with a mammary epithelial neoplasm, these three factors were also significantly associated with the odds of diagnosis with a malignant lesion and of diagnosis with multiple lesions. Notably, while neutered animals were less likely to have a mammary epithelial neoplasm diagnosed, and were less likely to have multiple neoplasms, they were more likely to have malignant disease. Exploration of the patterns of risk of developing malignant disease, or multiple lesions, across individual breeds showed no breed with increased odds of both outcomes. Breeds with altered odds compared to the Crossbreed baseline were either at increased risk of malignant disease and decreased risk of multiple lesions, or vice versa, or they were at significantly altered odds of one outcome with no change in the other outcome. Our analysis supports the hypothesis that age, neuter status and intrinsic biological and genetic factors all combine to influence the biological heterogeneity of canine mammary neoplasia.

Comparative Evaluation of Tumor-Infiltrating Lymphocytes in Companion Animals: Immuno-Oncology as a Relevant Translational Model for Cancer Therapy

Simple Summary

Laboratory experiments studying solid tumors are limited by the inability to adequately model the tumor microenvironment and important immune interactions. Immune cells that infiltrate the tumor bed or periphery have been documented as reliable biomarkers in human studies. Veterinary oncology provides a naturally occurring cancer model that could complement biomarker discovery, clinical trials, and drug development.

Abstract

Despite the important role of preclinical experiments to characterize tumor biology and molecular pathways, there are ongoing challenges to model the tumor microenvironment, specifically the dynamic interactions between tumor cells and immune infiltrates. Comprehensive models of host-tumor immune interactions will enhance the development of emerging treatment strategies, such as immunotherapies. Although in vitro and murine models are important for the early modelling of cancer and treatment-response mechanisms, comparative research studies involving veterinary oncology may bridge the translational pathway to human studies. The natural progression of several malignancies in animals exhibits similar pathogenesis to human cancers, and previous studies have shown a relevant and evaluable immune system. Veterinary oncologists working alongside oncologists and cancer researchers have the potential to advance discovery. Understanding the host-tumor-immune interactions can accelerate drug and biomarker discovery in a clinically relevant setting. This review presents discoveries in comparative immuno-oncology and implications to cancer therapy.

Strain and Shear-Wave Elastography and Their Relationship to Histopathological Features of Canine Mammary Nodular Lesions

Mammary gland tumours have a significant impact on the health of dogs, requiring diagnostic tools to support clinicians to develop appropriate therapeutic strategies. Sonoelastography is an emerging technology that is able to define the stiffness of the tissue and has promising applications in the evaluation of mammary gland lesions. In the present study, strain elastography (STE) and shear-wave (SWE) elastography were compared in 38 mammary nodular lesions for their ability to define the histopathological features of canine mammary lesions. Among the techniques, SWE showed better repeatability (intraclass correlation coefficient: 0.876), whereas STE was found to be only acceptable (intraclass correlation coefficient: 0.456). Mammary nodular lesions showed a wide range of tissue stiffening with a similar mean value for STE and SWE in benign (4 ± 0.3 and 115.4 ± 12.6 kPa, respectively) and malignant lesions (3.8 ± 0.1 and 115.5 ± 4.5 kPa, respectively). A significant correlation was found between lesion fibrosis and STE (STE-I: r = 0.513, p < 0.001; STE-R: r = 0.591, p < 0.001) or SWE-S (r = 0.769; p < 0.001). In conclusion, SWE was reliable and correlated with fibrosis and was similar for both benign and malignant lesions, suggesting that other collateral diagnostic techniques should be considered in conjunction with SWE to characterize mammary nodular lesions in dogs.

Establishment of stable expression of firefly luciferase and EGFP in a canine inflammatory mammary carcinoma cell line and tumor-bearing model in nude mice

Canine inflammatory mammary carcinoma (CIMC) is a type of canine malignant mammary tumor with a poor prognosis and high mortality. We transduced firefly luciferase and enhanced green fluorescent protein (EGFP) into CHMp, a CIMC cell line, and established CHMp-Luc-EGFP cells. We investigated the characteristics of this cell line in vitro and in vivo. CHMp-Luc-EGFP was passaged continuously 75 times, with stable expression of luciferase and EGFP. Compared with the wild-type, CHMp-Luc-EGFP had similar proliferation, metastasis, histopathology characteristics, and expression of E-cadherin, N-cadherin, and Ki-67. A tumor-bearing model was established by implantation of CHMp-Luc-EGFP cells, and the dynamic changes of tumors were visualized and quantified using the IVIS imaging system. In summary, the cell line we established could reflect the biological characteristics of CHMp cells, visualize the tumor progression in vivo, and provide a powerful tool for the study of CIMC.

Inflammatory Related Reactions in Humans and in Canine Breast Cancers, A Spontaneous Animal Model of Disease

Inflammatory cells are emerging markers in various cancers in human trials. The relationship between the inflammatory cells response, cancer grade, and progression has been investigated experimentally in a spontaneous canine model of breast cancer and in the unselected population (18–64 years.o.) under anti-HER2 treatments that represent the most prevalent population in this cancer type. The canine data (N samples = 101) were collected retrospectively for diagnosis in our regional area and evaluated by immunohistochemistry and haemato-chemistry. The inflammatory and immune-related adverse reactions (ADR) in humans were evaluated using EudraVigilance. The “Proportional Reporting Ratio” (PRR) of the mabs was calculated for each ADR with values >2 indicative of high risk. In dogs, we found elevated immunostaining of CD68-macrophages in the lymph node of the aggressive cancer G3 and infiltrating CD20+-lymphocyte. A high density of CD20 + lymphocytes was observed in G1 and a decrease in the density was observed with the histological degree of the tumors. The animals with the sample in G1 showed reduced serum platelet and neutrophil count and elevated lymphocytes and the opposite in severely affected animals. Inflammatory reactions with edema, skin reactions, extravasation, loss of effectiveness, and platelet count decrease (PRR > 13) were found with trastuzumab emtansine in humans, in the absence of immune system reactions. Trastuzumab i.v.-s.c. showed immune system reactions, loss of effectiveness, intolerances with drug withdrawal, technological issues (PRR > 7), and neutrophil count decrease reports. These reactions were less frequently reported for pertuzumab i.v. Case reports of platelet and neutrophil count decrease were not associated with disease progression with a better outcome in humans as in canine breast cancer. Therefore, infiltrating CD68-macrophages are associated with G3, while infiltrating CD20⁺ and elevated serum lymphocytes in parallel with reduced platelet and neutrophil count play a favorable role in human and canine breast cancer.

Comparison between Histological Features and Strain Elastographic Characteristics in Canine Mammary Carcinomas

Elastography is a sonographic technique that provides a noninvasive evaluation of the stiffness of a lesion. The objective of this work was to evaluate the accuracy of strain elastography, the most accessible modality in clinical practice, to discriminate between different histological types of malignant mammary neoplasms in the canine species, which can provide complementary information in real time to the diagnosis and thus help in the choice of surgical technique. A total of 34 females with 56 mammary carcinomas were selected and classified into three histological groups according to their aggressiveness. The histological and elastographic characteristics of these malignant tumors were analyzed and compared to evaluate the diagnostic accuracy of strain elastography. Visual score presented a sensitivity of 88.0%, specificity of 58.1%, and accuracy of 71.43% in distinguishing the most aggressive group of carcinomas. The strain ratio had a sensitivity of 84.0%, specificity of 61.1%, and accuracy of 69.64%. On the other hand, intratumoral strain ratio obtained a sensitivity of 71.40% and specificity of 61.90% when intratumoral fibrosis was taken as reference, with an accuracy of 66.07%. Similarly, peritumoral strain ratio was also positively related to fibrosis in the periphery of lesions (p ≤ 0.001), with a sensitivity of 93.80%, specificity of 77.50% and an accuracy of 92.87%. In conclusion, accuracy of this elastographic modality can be a useful method to differentiate more aggressive histological types. Therefore, it represents an additional diagnostic technique useful in the daily clinic thanks to the short time required for the examination, which allows real-time visualization and immediate interpretation of the results.

Natural COX-2 Inhibitors as Promising Anti-inflammatory Agents: An Update

COX-2, a key enzyme that catalyzed the rate-limiting steps in the conversion of arachidonic acid to prostaglandins, played a pivotal role in the inflammatory process. Different from other family members, COX-2 was barely detectable in normal physiological conditions and highly inducible during the acute inflammatory response of human bodies to injuries or infections. Therefore, the therapeutic utilization of selective COX-2 inhibitors has already been considered as an effective approach for the treatment of inflammation with diminished side effects. Currently, both traditional and newer NSAIDs are the commonly prescribed medications that treat inflammatory diseases by targeting COX-2. However, due to the cardiovascular side-effects of the NSAIDs, finding reasonable alternatives for these frequently prescribed medicines are a hot spot in medicinal chemistry research. Naturallyoccurring compounds have been reported to inhibit COX-2, thereby possessing beneficial effects against inflammation and certain cell injury. The review mainly concentrated on recently identified natural products and derivatives as COX-2 inhibitors, the characteristics of their structural core scaffolds, their anti-inflammatory effects, molecular mechanisms for enzymatic inhibition, and related structure-activity relationships. According to the structural features, the natural COX-2 inhibitors were mainly divided into the following categories: natural phenols, flavonoids, stilbenes, terpenoids, quinones, and alkaloids. Apart from the anti-inflammatory activities, a few dietary COX-2 inhibitors from nature origin also exhibited chemopreventive effects by targeting COX-2-mediated carcinogenesis. The utilization of these natural remedies in future cancer prevention was also discussed. In all, the survey on the characterized COX-2 inhibitors from natural sources paves the way for the further development of more potent and selective COX-2 inhibitors in the future.

Impact of Histological Subtype on Survival in Canine Mammary Carcinomas: a Retrospective Analysis of 155 Cases

Canine mammary carcinoma (CMC) is the most common type of neoplasm in intact female dogs. While a previous study in Western countries validated the 2011 classification as an independent prognostic indicator in CMC, its role in CMC prognostication in Asian countries such as Korea remains unclear. In the present study, we estimate the survival rates in CMC types defined by the 2011 classification, elucidate the prognostic significance of the histological subtype and grade and that of the lymphatic invasion status in CMC, and validate the 2011 classification as an independent prognostic indicator in a large cohort of CMCs (excluding cases of multicentric CMCs). A total of 155 CMC cases retrieved from archived formalin-fixed, paraffin-embedded tissues, along with 2-year follow-up data, were retrospectively analysed. A significant association was found between the histological subtype of the 2011 classification and the tumour-specific survival. Carcinosarcoma, adenosquamous carcinoma and anaplastic carcinoma subtypes were associated with the poorest prognosis. Dogs with comedocarcinoma and solid carcinoma followed a disease course that was more aggressive than that observed in dogs with a carcinoma arising in a benign mixed tumour. Moreover, age, histological grade and lymphatic invasion status significantly correlated with tumour-specific survival in univariate analysis. In multivariate analysis, histological subtype, age and lymphatic invasion status remained independent prognostic factors for CMC.

Prognostic significance of immunohistochemical markers and histological classification in malignant canine mammary tumours

Canine mammary carcinoma represents a model for the study of human breast cancer, although the prognostic value of various clinical, histological and immunohistochemical parameters has shown contradictory results. A prospective study, through a 4‐year follow‐up, was performed in 77 patients with mammary carcinoma to analyse the association between histological diagnosis, grade of malignancy, peritumoral and vascular invasion. We have also performed immunohistochemistry for the expression of oestrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and cyclooxygenase‐2 (COX‐2) that define human biomarkers of disease progression and treatment response. An association between histological diagnosis and clinical stage was observed with a high proportion of complex carcinoma classified as stage I. There was a higher proportion of ER⁺/PR⁺/HER2⁻ tumours in stage I. In contrast, triple‐negative tumours (ER⁻/PR⁻/HER2⁻) were found mainly in advanced clinical stages and were associated with vascular and peritumoral invasion. The tumours included in group VII (carcinosarcoma/adenosquamous carcinoma/other special types of carcinoma) had a higher expression of COX‐2. The univariate analysis showed that those patients with complex carcinoma had the lowest incidence of metastases and the highest probability of survival. In contrast, a high proportion of patients with anaplastic/inflammatory carcinoma developed metastases and showed the lowest probability of survival. In addition, the estimated survival time was shorter for those patients with triple‐negative tumours and those with high COX‐2 expression. However, in the multivariate analysis, only the peritumoral invasion maintained its prognostic significance. In conclusion, in our study anaplastic/inflammatory carcinomas had the worst prognosis with a high proportion of triple‐negative tumours in this category.