Prognostic markers of canine mammary tumours: Retrospective study of 142 cases

Due to relevance of the problem, prediction of biological behaviour of neoplasias in mammary glands of dogs requires using contemporary approaches to the study, first of all, of ways of dissemination of tumour cells. One of them is studying the mechanisms of migration of cancer cells out of the neoplasm tissues with further dissemination and development of metastatic sites in the regional lymphatic nodes and remote tissues. We studied the survival period of bitches with tumours of the mammary glands following regional or unilateral mastectomy. Among malignant mammary tumours in bitches, the most often diagnosed were single tumours (57.5%), which histologically were classified to carcinomas – ductal (26.9%) and mixed type (21.9%). Probability of intratumoral invasion to blood vessels equaled 12.0%, to lymph vessels – 7.8%, lymph nodes – 12.8%. It depends on the histological type of the tumour, the most aggressive potentially being сomedocarcinoma, tubulopapillary carcinoma and ductal carcinoma. Parameters of life expectancy and survival level after mastectomy depend on clinical stage of the disease (increase in the stage from the first to the third was characterized by decrease from 12.8 ± 9.5 to 9.4 ± 7.8 months), presence of angio/lymphatic invasions, presence of angiolymphatic invasion, but had no correlation with the size of the tumours. An important predictor of tumour-related death of dogs suffering neoplasias of the mammary glands is index vet-NPI, which has significant correlation with the clinical stage according to Owen and median survival. In particular, median survival in patients with the index lower than 4 exceeded the corresponding values in dogs with the index above 4 by 1.3 times. A promising direction of further research would be studying biological mechanisms of development of tumour emboli in the blood and lymph vessels, metastatic sites in lymph nodes, and also determining their role in pathogenesis of canine mammary tumours.

Deletion of Col15a1 Modulates the Tumour Extracellular Matrix and Leads to Increased Tumour Growth in the MMTV-PyMT Mouse Mammary Carcinoma Model

Basement membrane (BM) zone-associated collagen XV (ColXV) has been shown to suppress the malignancy of tumour cells, and its restin domain can inhibit angiogenesis. In human breast cancer, as well as in many other human carcinomas, ColXV is lost from the epithelial BM zone prior to tumour invasion. Here, we addressed the roles of ColXV in breast carcinogenesis using the transgenic MMTV-PyMT mouse mammary carcinoma model. We show here for the first time that the inactivation of Col15a1 in mice leads to changes in the fibrillar tumour matrix and to increased mammary tumour growth. ColXV is expressed by myoepithelial and endothelial cells in mammary tumours and is lost from the ductal BM along with the loss of the myoepithelial layer during cancer progression while persisting in blood vessels and capillaries, even in invasive tumours. However, despite the absence of anti-angiogenic restin domain, neovascularisation was reduced rather than increased in the ColXV-deficient mammary tumours compared to controls. We also show that, in robust tumour cell transplantation models or in a chemical-induced fibrosarcoma model, the inactivation of Col15a1 does not affect tumour growth or angiogenesis. In conclusion, our results support the proposed tumour suppressor function of ColXV in mammary carcinogenesis and reveal diverse roles of this collagen in different cancer types.

Evaluation of post-operative complications after mastectomy performed without perioperative antimicrobial prophylaxis in dogs

Background Mastectomy is the most common procedure for treatment of mammary tumours. Dogs undergoing mastectomy have a risk of developing surgical site infections (SSI) and other postoperative complications. However, potential risk factors associated with such complications have been sparsely investigated. Thus, the objective of this retrospective study was to determine the incidence of, and identify risk factors for, SSI and non-SSI postoperative complications after mastectomy performed without perioperative antimicrobial prophylaxis in privately owned otherwise clinically healthy dogs. Results Medical records were reviewed retrospectively for 135 client-owned female dogs, 10–35 kg in weight and three to 10 years of age, which had undergone mastectomy due to mammary tumours at three referral animal hospitals in Sweden over a 3-year period. Twelve (8.9%) dogs developed SSI, and 21 dogs (17.1%) dogs suffered a non-SSI postoperative complication. The incidence of SSI and all complications (SSI and non-SSI) were higher in dogs that had two to three (SSI: P = 0.036 and all complications: P = 0.0039) and four to five (SSI and all complications: P = 0.038) mammary glands excised, compared to dogs that had one mammary gland excised. The incidence of SSI was 1.7% (n = 1/60) in dogs that had one gland removed. The incidence of non-SSI postoperative complications was higher in dogs with a higher body weight (P = 0.02). Conclusions The incidence of SSI was lower than or similar to previously reported incidences of SSI in dog populations that have undergone tumour excisional surgery, despite the fact that dogs in the present study had not received perioperative antibiotics. Dogs that had two or more glands excised had an increased risk of developing SSI and non-SSI complications compared to dogs that had one gland excised. Furthermore, higher BW was associated with an increased risk of non-SSI complications. Results from the study indicate that routine use of perioperative antibiotics in tumour excisional surgery can be questioned, at least in single gland mastectomy in otherwise clinically healthy dogs.

Biochemical and histopathological evaluation of an in vivo model of breast cancer

Though, the clinical management of breast cancer has improved significantly over the past 30 years, it still remains the leading cause of cancer-related female death worldwide. Prevention is the fundamental issue in breast cancer control, for which identification markers in terms of initiation and promotion are necessary. To understand this, an animal model which can recapitulate the early symptoms of breast cancer development and progression is required. Present study is an attempt to develop a convenient and economical in-vivo animal model of breast cancer suitable to conduct such study. Female Wistar and SD rats were injected with different doses and routes of administration of 7, 12-Dihydroxymethylbenz (a) anthracene (DMBA). Animals were observed for the presence of visible/palpable tumours in mammary glands. Various parameters (Tumor morphology, oxidative stress and histopathological studies were studied in different tissues (mammary, lungs, kidney, liver) after the appearance of mammary tumours in rats. After 14 weeks all the animals developed breast carcinomas. The results of this study revealed a significant difference in oxidative stress parameters between DMBA treated and control groups and these alterations were strain dependent. The H&E staining of mice mammary tissue showed development of metaplastic triple negative breast cancer. Immunohistochemistry observation confirmed the triple negative nature of mammary tumours developed in the mice. Data confirmed that DMBA can be used as breast cancer initiator and present model can be further exploited to screen potential anti-breast cancer compounds in vivo.

Ovarian cycle stage critically affects 21-gene recurrence scores in Mmtv-Pymt mouse mammary tumours

Background The Oncotype DX 21-gene Recurrence Score is predictive of adjuvant chemotherapy benefit for women with early-stage, estrogen receptor (ER)-positive, HER2-negative breast cancer. In premenopausal women, fluctuations in estrogen and progesterone during the menstrual cycle impact gene expression in hormone-responsive cancers. However, the extent to which menstrual cycling affects the Oncotype DX 21-gene signature remains unclear. Here, we investigate the impact of ovarian cycle stage on the 21-gene signature using a naturally cycling mouse model of breast cancer. Methods ER-positive mammary tumours were dissected from naturally cycling Mmtv-Pymt mice at either the estrus or diestrus phase of the ovarian cycle. The Oncotype DX 21-gene signature was assessed through quantitative real time-PCR, and a 21-gene experimental recurrence score analogous to the Oncotype DX Recurrence Score was calculated. Results Tumours collected at diestrus exhibited significant differences in expression of 6 Oncotype DX signature genes (Ki67, Ccnb1, Esr1, Erbb2, Grb7, Bag1; p ≤ 0.05) and a significant increase in 21-gene recurrence score (21.8 ± 2.4; mean ± SEM) compared to tumours dissected at estrus (15.5 ± 1.9; p = 0.03). Clustering analysis revealed a subgroup of tumours collected at diestrus characterised by increased expression of proliferation- (p < 0.001) and invasion-group (p = 0.01) genes, and increased 21-gene recurrence score (p = 0.01). No correlation between ER, PR, HER2, and KI67 protein abundance measured by Western blot and abundance of mRNA for the corresponding gene was observed, suggesting that gene expression is more susceptible to hormone-induced fluctuation compared to protein expression. Conclusions Ovarian cycle stage at the time of tissue collection critically affects the 21-gene signature in Mmtv-Pymt murine mammary tumours. Further studies are required to determine whether Oncotype DX Recurrence Scores in women are similarly affected by menstrual cycle stage.

XENOBREAST Trial: A prospective study of xenografts establishment from surgical specimens of patients with triple negative or luminal b breast cancer

Introduction: Patient-derived xenografts (PDX) can be used to explore tumour pathophysiology and could be useful to better understand therapeutic response in breast cancer. PDX from mammary tumours are usually made from metastatic tumours. Thus, PDX from primary mammary tumours or after neoadjuvant treatment are still rare. This study aims to assess the feasibility to establish xenografts from tumour samples of patients with triple negative or luminal B breast cancer in neoadjuvant, adjuvant or metastatic setting. Methods: XENOBREAST is a single-centre and prospective study. This feasibility pilot trial aims to produce xenografts from tumour samples of patients with triple negative or luminal B breast cancer. Patient enrolment is expected to take 3 years: 85 patients will be enrolled and followed for 28 months. Additional blood samples will be taken as part of the study. Surgical specimens from post-NAC surgery, primary surgery or surgical excision of the metastases will be collected to establish PDX. Histomolecular characteristics of the established PDX will be investigated and compared with the initial histomolecular profile of the collected tumours to ensure that they are well-established. Ethics and dissemination: XENOBREAST belongs to category 2 interventional research on the human person. This study has been approved by the Sud Méditerranée IV – Montpellier ethics committee. It is conducted notably in accordance with the Declaration of Helsinki and General Data Protection Regulation (GDPR). Study data and findings will be published in peer-reviewed medical journals. We also plan to present the study and all data at national congresses and conferences. Registration: ClinicalTrials.gov ID NCT04133077; registered on October 21, 2019.

In silico evaluation of phytocompounds from Indian medicinal plants for Canine Mammary Tumours

Canine mammary tumours are among the most predominant neoplasms and happen all the more usually among unblemished females which are not spayed at an early age. The previous study carried out at Madras Veterinary College reported that out of the 14,326 clinical cases presented in an eight months study, 61 cases were mammary tumours. The current study was aimed to screen chemo preventive effect of phytocompounds of Indian medicinal plants for Canine mammary tumours. Mammaglobin-B was taken as a target protein and it was modeled using I-Tasser. Around 920 phytocompounds were collected from different Indian medicinal plants using Dr. Duke’s database. In which, after checking Lipinski Rule of five, 132 compounds were selected for this study. The 3D structure of all the phytocompounds were retrieved from PubChem database. Docking studies were done using Discovery Studio 4.0. From the results, the phytocompounds Homocapsaicin (Libdcok score: 102.27), Homodihydrocapsaicin (Libdcok score: 101.55) and Isositsirikine (Libdcok score: 99.19) showed the best Libdcok score. Hence, the present study was concluded that the phytocompounds Homocapsaicin and Homodihydrocapsaicin from Capsicum annuum and Isositsirikine from Catharanthus roseus had potential effect against Canine mammary tumours.