Correlation Between Plasma Circulating Tumor DNA And Clinicopathological Factors Of Ovarian Cancer

Objective:The expression of DNA in circulating tumor was detected by the second generation sequencing analysis of chromosome copy number variation before operation in patients with benign and malignant ovarian tumors.To discuss the value of circulating tumor DNA in the diagnosis of benign and malignant ovarian tumors and its correlation with clinicopathological factors of ovarian malignant tumors.Methods:From January 2017 to May 2018,92 patients with ovarian tumors were treated in Qingdao Municipal Hospital,including 32 benign ovarian tumors,4 borderline ovarian tumors and 56 ovarian malignant tumors.Venous blood was taken before operation,and the variation and expression of DNA chromosome copy number in plasma circulating tumors were detected by second generation sequencing.Venous blood was taken for CA125 detection before operation,and the clinicopathological data were analyzed.To analyze the expression of ctDNA in benign and malignant ovarian tumors,and to explore the value of ctDNA in the diagnosis and differential diagnosis of benign and malignant ovarian tumors.The relationship between preoperative blood ctDNA content and clinicopathological features,such as blood CA125,tumor size,clinical stage,histological grade,pathological type and related immunohistochemical indexes,was analyzed.To further investigate the expression of ctDNA in ovarian cancer with different clinicopathological features and its possible influencing factors.Results:In 32 cases of benign ovarian tumors,2 cases were positive for ctDNA before operation,4 cases of borderline tumor were negative for ctDNA before operation,and 39 cases of 56 cases of ovarian malignant tumor were positive for ctDNA before operation.The positive rate was 69.6%(39/56),the difference was statistically significant(P<0.05).In 56 cases of malignant ovarian tumors,the positive rate of CA125 in blood was 85.71%,and the positive rate of ctDNA was 69.6% before operation,there was no significant difference between the two groups(P>0.05).In addition,it was found that chromosome copy number variation mainly occurred in 2Q,3q,6p,8q,mainly in amplification.The positive rate of ctDNA before operation was correlated with tumor size,clinical stage,histological grade and pathological type.The larger the tumor was,the later the stage was,and the lower the degree of differentiation was,the higher the positive rate of ctDNA before operation was.The positive rate of ctDNA was 79.5% in serous ovarian carcinoma and 47.1% in non-serous ovarian carcinoma(P < 0.05).Among 39 patients with ctDNA positive ovarian cancer before operation,29(74.4%)had p53 mutation in immunohistochemical staining,and 10(25.6%)were negative(P < 0.05).There was a significant difference between the two groups(P < 0.05).Conclusion:1.ctDNA chromosome copy number variation can be detected in the blood of ovarian malignant tumors before operation,and the detection rate in benign ovarian tumors is very low.Therefore,ctDNA can provide a reference for the diagnosis and differential diagnosis of benign and malignant ovarian tumors.2.There is no difference in the positive rate of ctDNA and CA125 in blood before operation for ovarian malignant tumors.It is suggested that preoperative blood ctDNA,like CA125,can be used as a new "liquid biopsy" method for the diagnosis of ovarian malignant tumors.3.The variation of plasma ctDNA chromosome copy number mainly occurred on 2q,3q,6p,8q chromosomes before operation in patients with ovarian cancer.Amplification was more than deletion.It is suggested that the pathogenesis and progression of ovarian cancer may be changed at the molecular level.4.The detection rate of plasma ctDNA chromosome copy number variation in ovarian cancer before operation was correlated with tumor size,clinical stage,histologic grade,p53 mutation and pathological type.The bigger the tumor was,the later the clinical stage was,the lower the histological differentiation degree was,the higher the detection rate of plasma ctDNA,the higher the detection rate of serous ovarian carcinoma was significantly higher than that of non-serous ovarian carcinoma.The positive rate of plasma ctDNA was higher in patients with p53 mutation before operation.