Ul Trasonic Characteristics Of Human Breast Cancer With The Tumor Growth In Nude Mice Model

Objective:Ultrasonography plays an extremely important role in the detection and the monitoring of treatment and prognosis of breast cancer.However,with the growth of tumor,its changes of the morphology and internal structure are in a dynamic process.So the imaging features are not identical at different stages of tumor development,which has brought about certain interference information for the differential diagnosis of tumors and evaluation of treatment effects.Therefore,this research was planned to establish an animal model of orthotopic transplantation of human breast cancer in nude mice and detect the tumors by ultrasound at different time points.To explore the characteristics of sonographic changes of breast cancer with tumor growth.Methods:Thirty BALB/c athymic nude mice were used to establish an orthotopic xenograft model of human triple-negative breast cancer.Tumor volume,shape,border and echo changes were observed by ultrasound every three days.the morphological characteristics of tumor vessels was observed by color Doppler ultrasound.The number of blood flow signals,peak systolic velocity of blood flow and resistance index were measured.Repeated measures analysis of variance was used to compare blood flow measurements of tumors at different time points,the results was statistically dealt with.Then Micro-Vascularization imaging was turned on and the paired t test was used to compare the blood flow detection capabilities of the two blood flow imaging techniques.The lesions of four tumors growing for 9 days,15 days,21 days and 27 days,respectively,were Paraffin-embedded.Then the histological sections were obtained and stained with Hematoxylin-Eosin to observe the cell and structural changes of the tumor tissues under a microscope.Results:Twenty-seven of thirty nude mice(90%)ere successfully established as an orthotopic transplantation animal model,and nineteen of these animal models(70%)were used for this study.Ultrasonography results: as was showed in the growth curve of tumors,the volume development rate declined rapidly after early rapid rise.In the post-transplant period of 9 to 21 days,the rate of volume development of twelve(63%)were up to 200% or higher.The changes of tumor morphology were from irregularity to oval or ellipse and then became microlobulated shape with tumors' growth,and eight tumors(42%)showed oval or oval shape on the 9th day,then seven of tumors(37%)had became microlobulated shape on the 21 st day.Undefined boundaries of tumor at beginning gradually became clear.on the 9th day,eleven tumors' boundaries(58%)were clear.With the rapid growth of tumors,the internal echo was changed from heterogeneous hyperechoic to homogeneous hypoechoic and then became heterogeneous high echo again.Three tumors(16%)became sieve-like hypoechoic on the 9th day.with the necrosis appearance,three tumors(16%)were heterogeneous high echo on the 21 st day.Seventeen of nineteen(89%)tumors showed rear echo enhancement at different time points,and this ultrasonic feature was mainly in the period of rapid volume development,with fifteen tumors(79%)occurring on the 18 th day.Blood flow imaging: only three tumors(16%)could be detected dot-like or short rod-like blood flow signals on the 6th day.On the 9th day,branch blood flow signal occurred in one of fourteen tumors which were detected the vessels.With the sustained development of tumors,dot-like and rod-like and branch-like blood flow signals coexisted.The tumor vessels were disordered,distorted,multi-branched,and the diameters of vessels were different.The quantity of blood vessels,peak systolic velocity and resistance index showed an increasing tendency,but the measured data of each tumor at different time points were fluctuant,with an statistical significant difference(p<0.05).Compared the ability of Micro-Vascularization imaging with the ability of color Doppler flow imaging to detect blood flow signals through blood vessel counts,the difference was statistically significant(p<0.05).Histopathological examination showed that the ratio of cytoplasm in four tumors was high.The shape of nuclei was different.The heteromorphism and the degree of malignancy was high and more mitotic figures.Two of the tumors showed a small amount of duct formation and two showed interstitial focal infiltration of lymphocytes and neutrophils.Large necrosis and small calcifications of tumors was found in the tumor of 27 days.Conclusions:An animal model of human breast cancer in nude mice can be successfully established by the orthotopic xenografts of tumor tissue pieces.Animal models can be used to study the natural growth process of breast cancer in vivo.With the development of breast cancer,morphological changes of tumors are regularity.The numbers of blood flow signals and the hemodynamic parameters generally have an increasing trend,but the measurements of blood flow are fluctuations with affecting from their own and external factors.Ultrasonography was used to study the characteristics of natural changes in breast cancer,laying a foundation for subsequent studies on biological characteristics,diagnosis and treatment of breast cancer.