Breast Cancer Animal Models And Its Evolution Characteristics Of Ultrasonic Imaging And Pathological Study

Part One Study of the Histological Changing of Breast Tumor in SD Rats Induced by DMBA in Occurrence and DevelopmentTo investigate the change of the histology and pathology in DMBA—induced breasttumor rat model and provide lab foundation of pathologic change and some clue in early diagnosis of breast cancer in human1. Divided55female SD rats into two group randomly:drug group (n=50) and controlgroup (n=5)2. Administer high dose(150mg/kg) DMBA in drug group and same dose of peanut oil in control group by gastrogavage3. In drug group after gastogavage, ultrasound examination of breast tissue or tumor in2-5rats randomly selected every week from5week (w) to20week4. To take the breast tissue HE staining and to analyse histopathologically.1. Rate of tumor.0%in control group,0%in5-7w,50%in8-10w,73%in11-13w,100%in14-16w and100%in17-20w after administration.2. Size of tumor,1.47±0.4cm in8-10w,1.82±0.79cm in11-13w,1.51±0.84cm in14-16w,2.72±1.24cm in17-20w after administration.3. Histological type, ductal carcinoma in situ (n=3), invasive carcinoma (n=79),carcinosarcoma (n=1), cystosarcoma phyllodes (n=1) and fibroadenoma (n=1)4. Histological changes at pre-neoplasia stage. hyperplasia (n=7); Small ducts withsigns of cell death and increased number of lobules in5-7w after administration compared with control group, but there was not significant difference between two groups (p>0.05)Conclusions1. Improved breast tumor rat model with high dose DMBA by gastrogavage to achieve high rate of tumors. All stages of breast tumor are observed including normal tissue, hyperplasia, carcinoma in situ and invasive cancer.2. Summarize the characteristics of the histological changes in pre-hyperplasic stage of DMBA induced rat breast cancer, providing important basis for breast imaging in pre-hyperplasic stage. Part Two Evaluation by ultrasound Imaging of the Occurrence and Development of DMBA-Induced Breast Tumor in SD Rats and Compared with HistologyObjective:To investigate breast tumorigenesis and angiogenesis by grey-scale imaging, color Doppler ultrasound imaging (CDFI) and contrast enhanced ultrasound (CEUS). By compared the finding of ultrasound and pathology, to explore the regulartity of morphology, vascular occurrence and evolution of breast cancer, thus providing the laboratory base for diagnostic ulrtrsound.Methods1. Group divided method and modeling see part one.4rats had been selected randomly into continuous observation group from drug group.2. Ultrasound examination including grey-scale imaging, CDFI and CEUS of breast tissue or tumor in2-5rats randomly every week from5week (w) to20week after gastogavage3. In continuous observation group, the ultrasound examinztions were applied in breast tissue or tumor of rats from6(8)w to16w with grey-scale imaging, CDFI and CEUS.4. To take the breast tissue HE staining and to analyse histopathologically.Result:1. Tumor Size(Length):Divided into4groups by tumor size (L):group1(L≤1cm,13.75±2.1w), group2(L=1-2cm,13.97±2.5w), group3(L=2-3cm,14.83±3.1w) group4(L>3cm,16.6±3.9w)2. Ultrasound image feature. At pre-neoplasia stage, no change was found in grey-sale imaging and CDFI, but concentration enhancement (56%) and no concentration enhancement (44%) were found in CEUS. At mass stge, with the increasing of the size of the mass(from<lcm to>3cm), the echotexture of the mass changed from homogeneous(93.8%) to heterogeneous (60%) in grey-sale imaging; from no color signal(100%) to colorful signal(100%) in CDFI; from homogeneous enhancement (93.8%) to heterogeneous enhancement (100%) in CEUS. There were significant differences of ultrasound appeares between different size groups. Imaging features were correlated with size of tumor significnatly(p<0.05, r=1)3. Two breast masses were observed contiuously with CEUS, one was from concentration to homogeneous enhancement, another from homogeneous enhancement to heterogeneous enhancement.4-Compared the group of concentration with the group of no concentration in5-7w, in histological appearances of pre-hyperplasia. There were significant differences(p<0.05) in gland hypersecretion, small ducts with signs of cell death and increased number of lobules; The regresson analysis showed concentration in CEUS were correlated with small ducts with signs of cell death and increased number of lobules, was not correlated with gland hypersecretion.5. No-contrast enhanced area in CEUS was found in20lesions. histological appearances were necrosis lesions (n=15), pre-necrosis lesions(n=5), multiple lesion (n=4) and Interstitial Hyaline lesions(n=4).Conclusions1. Present tumorigenesis feature of ultrasound of DMBA-induced breast tumor of rats, which were from homogeneous echopattern at early stage to heterogeneous echopattern at late stage; from rapid growth to slow-down growth.2. Present tumor angiopoiesis feature of DMBA-induced breast tumor of rat in CEUS, which were concentration in preneoplastic stage that were obviously earlier than the appearance in grey-scale image; homogeneous enhancement in early stage and heterogeneous enhancement in late stage.3. Present the feature of vasculature in CEUS at hyperplasic and pre-hyperplasic stage, suggested that concentration in CEUS may be the start signal of tumorgenesis, which provided an important evidence for evaluation of breast tumor at pre-neoplasic stage.4. Using DMBA-induced breast cancer model to find the corresponding tumor growth way.Present pre-necrosis tumor tissue was the important component of the no enhanced area in CEUS, which was possibly potential risk factor responsible for the local recurrence of cancer.