| Background and Objective:Cervical cancer,ovarian cancer and endometrial cancer are the most common cancers of the reproductive tract system in women.Among them,ovarian cancer,especially high-grade serous carcinoma,has the highest recurrence rate and mortality.Surgery combined with radiotherapy and chemotherapy are currently the most important treatment for gynecologic malignancies.The current efficacy evaluation mainly relies on serum tumor markers and imaging tests such as ultrasound and MRI.With the development of second-generation sequencing technologies,research on tumors has gradually shifted to the molecular level.This research aims to explore the distribution of genetic mutations in gynecologic malignancies and the relationship between gene mutations and tumor mutation burden by analyzing the DNA of gynecologic tumors.In addition,plasma cell free DNA has been shown to be useful in the diagnosis,disease monitoring,and prognostic evaluation of tumors.We hope to study the value of plasma free DNA in gynecologic malignancies,especially ovarian cancer,by studying plasma cell free DNA in patients with ovarian cancer.Methods:? 117 patients with gynecologic malignancy were selected for analysis of DNA mutations in their tumor tissues,and the tumor mutational burden was calculated to analyze the relationship between gene mutation and tumor mutational burden;? A 100-bp DNA ladder as a standard test was used to compare the effect of the two DNA extraction methods,the magnetic bead extraction method and the spin column extraction method,on the isolation of small pieces of DNA.Sixty-eight ovarian cancer patients with both a blood sample and a tissue sample at the same time were selected to compare the mutations of BRCA1/2,PIK3CA,PTEN,and TP53 in the plasma cell free DNA and tumor tissue DNA,and their consistency was evaluated.We also acess the feasibility of plasma cell free DNA in ovarian cancer.?Twenty-two cases of ovarian cancer patients with a follow-up period of 6 months were selected to analyze the dynamic changes of plasma free DNA,and to explore the value of plasma cell free DNA in the evaluation of ovarian cancer prognosis;?Three cases of ovarian cancer patients with typical TP53 mutations were selected to compare the dynamic changes of TP53 mutations in plasma cell free DNA with tumor marker and imaging consistency,and to explore the value of plasma cell free DNAin clinical practice.Results:? The most common gene mutations in gynecologic malignancies are TP53,PIK3CA,and PTEN,and somatic mutations in the BRCA gene are only found in patients with ovarian cancer.Compared with POLE,PTEN,and TSC2 wild type,patients with POLE,PTEN,and TSC2 mutations had higher TMB levels and the differences are statistically significant;? The two-step magnetic beads separation method is used to extract plasma cell free DNA with higher purity and quantity.Compared with DNA examination of tumor tissue,the sensitivity of the total mutation status of BRCA 1/2,PIK3CA,PTEN and TP53 in plasma cell free DNA is approximately 67%,specificity is approximately 97%,and accuracy is approximately 86%.Plasma cell free DNA can be used as an alternative way to detect gene mutations for the patients with ovarian cancer;?The most common mutated genes in plasma cell free DNA in patients with ovarian cancer are BRCA2(29%),ARID1A(26%),BRCA1(21%),TP53(21%),NF1(11%),TSC1(11%),and TSC2.(11%),depending on the patient's prognosis,the difference in BRCA2 mutations is statistically significant(p=0.04).Compared with serum tumor markers,dynamic monitoring of the 10 gene MMB(including genes AKT1,ARID 1 A,BRCA1,BRCA2,MTOR,PIK3CA,PTEN,TP53,TSC1,and TSC2)in 22 patients is better than that of ovarian cancer.Consistency.In addition,the 10 gene MMB levels in plasma cell free DNA were significantly lower after treatment in ovarian cancer patients with better prognosis than those with poorer prognosis(p=0.006);?Comparing the plasma cell free DNA results and clinical data of 3 cases of ovarian cancer patients with typical TP53 mutations,the dynamic changes of TP53 are consistent with the 10 gene MMB,which has a certain value for the detection of ovarian cancer.Conclusion:? This study obtained a gene mutation spectrum of gynecological malignancies,an overview of TMB,and mutations associated with high-to-moderate levels of TMB;? The magnetic bead method two-step separation method can be used to extract plasma free DNA,plasma cell free DNA detection and tumor tissue DNA detection consistency is higher,can be used for ovarian cancer patients.? Plasma cell free DNA can detect ovarian cancer gene mutations,and patients with ovarian cancer carrying BRCA2 mutations may have a better prognosis.At the same time,the dynamic detection of 10 gene MMB can be used to evaluate the prognosis of patients with ovarian cancer;? Plasma cell free DNA is expected to be used in a wider range of clinical applications,we need a larger-scale prospective study to verify the results. |
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