| Along with the increase in the number of dogs,there is also an increase in the number of cancer cases.Mammary gland tumors are the most common neoplasm diagnosed in older female dogs,accounting for nearly 50%.Nowadays,there is an increasing demand for treatment strategies and prognostic assessment of mammary gland tumors by pet owners.In order to improve the quality of life in cancer patients and to meet the needs of pet owners,while Seeking better treatment options and more accurate prognosis assessment in veterinary medicine the epithelial-mesenchymal transformation(EMT)of mammary gland tumors was studied.Epithelial-mesenchyme transformation(EMT)is associated with the occurrence and development of mammary gland tumors.During this process,the expression of the epithelial marker,E-cadherin,is decreased,while the expression of mesenchyme markers,N-cadherin and Vimentin,are elevated.The expression transformation from E-cadherin to N-cadherin is an important mechanism of EMT.These EMT-related proteins play a crucial role in the development of mammary gland tumors,which impairs the integrity of tumor cytoskeleton,leads to a decrease in adhesion between cells,causes cells to lose polarity,results in tumor cell production,invasion and metastasis.In addition,the occurrence and development of canine mammary gland neoplasms are similar to that in human breast cancer,thus the canine model can be used for the study of EMT in human cancer.In this study,136 cases of canine breast tumors were collected from the animal hospital affiliated to Northeast Agricultural University and other animal hospitals in Harbin from May 2015 to July 2018.According to WHO classification criteria of histopathology and two authoritative experts of mammary gland tumors histopathology,the benign and malignant degree and subtypes of breast tumors were determined.By collecting the records of case histories of all female dogs in these animal hospitals during this period,the number of each breed with breast cancer were recorded.The food type,tumor location,age of onset,fertility and sterilization status of the dogs were also recorded.The relationships between the occurrence of canine breast tumors and these indicators were shown by processing data and making charts.Finally,the survey results were statistically analyzed.All tumor tissue samples were embedded into paraffin,sectioned and stained using the HE technique,after which the origin and character of tumor tissue were identified.For further study,the expressions of E-cadherin,N-cadherin,Vimentin and EZH2 in 53 malignant canine breast tumors were detected with immunohistochemistry.The relationship between their expression levels and clinicopathological characteristics of canine mammary gland tumors was discussed in order to provide theoretical basis for the application of these proteins in clinical diagnosis,prognosis evaluation and treatment.The results show that:(1)Epidemiological investigation revealed that 22 dog breeds were affected with mammary gland tumor in Harbin,and the predominant breeds were mixed-breed dogs and poodle.The incidence of mammary gland tumor was higher in dogs fed with self-made dog food,commercial dog food,human food and meat.The incidence of breast tumors in the posterior abdominal and inguinal breast regions were higher than that in other breast regions,and the left breast region was higher than the right breast region.With the increase in age,the incidence of canine breast tumors increased,and the highest incidence was seen in dogs approximately 9 years old.Sterilization before the first estrus can effectively prevent the occurrence of mammary gland tumor in dogs,and the number of births is negatively correlated with the incidence of mammary gland tumor.(2)The results of HE staining and pathological expertise show that benign mammary gland tumors accounted for 54.41%(74/136)including 23 cases of fibroadenoma,14 cases of intraductal papilloma,11 cases of lobular hyperplasia,10 cases of breast adenosis,9 cases of dermal fibroma and 7 cases of other benign mammary gland tumors.Malignant breast tumors accounted for 45.59%(62/136)including 41 invasive ductal carcinomas,6 intraductal carcinomas,5 squamous cell carcinomas,3 micropapillary carcinomas,3 ductal carcinoma in situ(DCIS)and 4 other malignant mammary gland tumors.(3)The results of immunohistochemical identification are as follow: E-cadherin protein mainly exists in the cell membrane,which is yellowish or brown in color,but fewer in the cytoplasm.The expression of E-cadherin was significantly lower in malignant canine breast tumors than in normal canine breast tissues.N-cadherin and Vimentin are mainly located in the cell membrane and cytoplasm of cancer cells,while EZH2 is mainly located in the nucleus of malignant tumor cells,and they are highly expressed in malignant mammary gland tumors.The relationship between the expression of EMT-related protein and clinicopathological factors in 53 cases of malignant canine breast tumors was analyzed by variance test.The results showed that the expression of E-cadherin was closely related to the metastasis and histological grade of canine breast tumors(P < 0.05).The level of E-cadherin significantly decreased in malignant canine breast tumors with high histological grade and high clinical stage(P < 0.05),but not related to age and size of tumors(P > 0.05).The expression of N-cadherin,EZH2 and Vimentin was closely related to histological grade(P < 0.05).The expression of N-cadherin,EZH2 and Vimentin was increased in malignant canine breast tumors with high histological grade(P < 0.05).There was no significant differences in the expression of N-cadherin,EZH2 and Vimentin protein between different types of malignant canine breast tissues(P > 0.05). |
PDF Full Text Request