CD82 In Exosome As A Biomarker For Early Diagnosis Of Breast Cancer

BackgroundAccording to data released by the National Cancer Statistics Center in 2018,breast cancer has surpassed lung cancer as the highest incidence of cancer in women.In our country,the number of newly diagnosed cases is about 270,000 per year.Experts point out that as early diagnosis and early treatment,the cure rate of breast cancer can reach more than 90%.However,due to the lag of diagnostic methods,most patients have missed the best diagnosis period.In Beijing,for example,the first diagnosis of stageⅠpatients accounted for only 32%.The current diagnosis of breast cancer also relies on color Doppler ultrasound,CT,fine needle aspiration biopsy and other methods,but they have shortcomings such as early screening and invasiveness.So actively looking for new markers for early diagnosis of breast cancer is imminent.Exosomes are microvesicles with a lipid bilayer structures between 30 and 150nm in diameter.Most cells excrete exosomes under physiological or pathological conditions.Exosomes are widely distributed in body fluids such as peripheral blood,Saliva,urine and amniotic fluid.Exosomes contain a wealth of protein and genetic material that can be transported to target tissues or target organs to perform their functions.CD82 belongs to the members of the transmembrane 4 superfamilyand is a widespread tumor suppressor.It is highly expressed in normal tissues and its expression reduced or absent,which is related to the occurrence and progression of various tumors.ObjectiveThe difference of level of CD82 between serum and plasma exosomes in healthy control group,benign breast disease group and malignant breast cancer group was analyzed,and the expression of CD82 in paraffin tissue sections was compared between the three groups.The correlation between the expression of CD82 in exosomes and the expression of CD82 in paraffin sections was investigated to show the value of CD82 in exosomes in the early diagnosis and prognosis evaluation of breast cancer.MethodTotally 240 subjects including 80 cases of malignant breast cancer,80 cases of benign breast disease and 80 age-matched healthy controls were enrolled in this study.The exosomes were extracted rapidly by precipitation method.Nanosight method was used to detect the exosome concentration and particle size distribution.ELISA and Western Blot were used to detect the exosome markers CD9 and CD63.ELISA method was used to detect the serum and plasma exosome CD82 content.Western Blot method to detect exosome CD82 content and serum and plasma CD82 content,using Image Studio Ver 4.0 software to calculate the protein optical density of the band.The expressionof CD82 inparaffintissuewasdetected by immunohistochemistry,and Image pro-plus 6.0 software analyzed the results,using the average optical density to quantify the expression of CD82 in tissues.Results1.Microvesicles with a diameter of 30-150 nm were detected in serum and plasma,and CD9 and CD63 expression was detected by ELISA and western Blot.2.Compared with patients with benign breast disease and healthy person,the expression of CD82 in breast cancer serum and plasma exosomes was significantly higher(P<0.05).3.The expression of CD82 in exosomes was significantly higher than that in peripheral blood and serum(P<0.05).4.Compared with benign breast disease tissues and adjacent normal breast tissues,the expression of CD82 in breast cancer tissue was significantly reduced(P<0.05).5.The expression of CD82 in the tissue was significantly correlated with the CD82content in exosome(r~2=0.7329,P=0.0019).Conclusion1.Use of the SBI kit enabled the successful extraction of morphologically intact exosomes from peripheral blood.2.Serum exosome CD82 levels in patients with malignant breast cancer were significantly higher than those in healthy controls and benign groups.With the increase of breast cancer staging,the content of CD82 was significantly increased.3.The content of CD82 in exosomes was significantly higher than that in serum and peripheral blood,indicating that CD82 is mainly in the form of exosomes in the blood of patients with breast cancer.4.The expression of CD82 inbreast cancer tissue was significantly lower than that in healthy group and benign breast disease group.There was a significant negative correlation between the expression of CD82 in tissues and the content of CD82 in exosomes,which indicated that the expression of CD82 was metastasized from tissue to blood with the development of breast cancer.