| Background and Objective: Precancerous breast disease is a group of different histologic definition of pathological changes,including the atypical ductal hyperplasia and ductal carcinoma in situ,etc.,are associated with an increased risk of breast cancer.It Study of precancerous lesions,in order to reduce breast cancer,it is worth exploring.At present,there are many studies on precancerous lesions of breast cancer,but there is a lack of good research tools,and the progress is slow.The academic community has been arguing about whether precancerous lesions are the only way to cancerization.This study aims to use MMTV-PyMT mouse model which is classical model of breast cancer to preliminary explore the precancerous lesions and its biological characteristics,of precancerous lesions in the breast cancer research provides powerful tool.Methods: 1.C57BL/6J mouse of 6,8,10,12 weeks of age were used as control group,MMTV-PyMT mouse were used as experimental group,and they were divided into 7 age groups,6,8,10,12,16,20,24 weeks of age respectively 2.The mammary glands of 6-,8-,10-,12-week-old C57BL/6J mouse and 6-,8-,10-,12-week-old MMTV-PyMT mouse were stained with carmin alum.3.Hematoxylin-eosin staining and immunohistochemical staining of estrogen receptor alpha,progesterone receptor,alpha-smooth muscle actin and cytokeratin 14 were performed on the mammary gland paraffin sections of 6-,8-,10-,12-week-old C57BL/6J mouse and 6-,8-,10-,12-,16-,20-,24-week-old MMTV-PyMT mouse.Results: 1.From the carmine staining of mammary gland of MMTV-PyMT mouse at 6weeks of age,the development of mammary gland began to be abnormal.HE staining results showed that ADH appeared in mammary duct,which had involved more than two ducts,which could be classified as carcinoma in situ.Combined with immunohistochemical indicators,it was more inclined to DCIS,and ERα and PR were not expressed,α-SMA and CK14 were expressed,which were lower than that of control group(P<0.05).2.The mammary gland of 8-week-old MMTV-PyMT mouse was abnormal by carmine staining,DCIS was found by HE staining,ERα and PR were not expressed,α-SMA and CK14 were expressed,and the expression was lower than that of the control group(P<0.05).3.In MMTV-PyMT mouse of 10 weeks old,the abnormal hyperplasia of mammary gland was increased by carmine staining,and the HE staining result showed that DCIS appeared in the mammary gland of mouse.Combined with immunohistochemical indicators,ERα and PR were not expressed,α-SMA and CK14 were still expressed,which were reduced compared with the control group(P<0.05).4.The results of carmine staining and HE staining showed that the mammary glands of 12-week-old MMTV-PyMT mouse were still DCIS,but the involved area were enlarged.Combined with immunohistochemical indicators,ERα and PR were not expressed,α-SMA and CK14 were still expressed,which were reduced compared with the control group(P<0.05).5.16 weeks old MMTV-PyMT mouse mammary gland began to form tumor,HE staining results showed that part of the invasive cancer,ERα,PR still did not express,α-SMA and CK14 still expressed,may be accompanied by DCIS.6.The mammary glands of MMTV-PyMT mouse aged 20 weeks were tumor-like,and HE staining showed that they were invasive carcinoma.Combined with immunohistochemical indicators,α-SMA negative expression could be judged as invasive carcinoma,and they did not express ERα,PR and CK14.7.24-week-old MMTV-PyMT mouse showed large breast tumors with ulceration.HE staining showed that they were invasive carcinoma.Combined with immunohistochemical indicators,α-SMA was negative,which supported the diagnosis of invasive carcinoma.They did not express ERα,PR and CK14.Conclusion: This study confirmed that MMTV-PyMT mouse developed DCIS at 6weeks of age,and from 6 weeks to 12 weeks of age,they were all DCIS,ERα and PR were not expressed. |
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