Detection of plasma exosomal miRNA-205 as a biomarker for early diagnosis and an adjuvant indicator of ovarian cancer staging

BACKGROUND: Ovarian cancer (OC) is one of the serious threats to the health of women worldwide, and accurate biomarkers are urgently demanded for early diagnosis of OC. We have previously confirmed that miR-205 promotes the invasion and metastasis of OC cells by inhibiting the expression of the tumor suppressor gene TCF21. In this study, we used liquid biopsy technology to detect the expression levels of the four genes, miR-205, CA125, HE4 and TCF21, in the exosomes of plasma of OC patients. Combined with analysis of clinicopathological parameters of OC patients, we aimed to provide efficient and non-invasive laboratory biomarkers for early diagnosis of OC. METHODS: 36 OC patients who were diagnosed in local hospitals from September 2020 to July 2021 were selected as OC group, 31 cases of surgically diagnosed with ovarian benign lesions were selected as benign group, and 32 healthy people who underwent physical examination during the same period were selected as a control group. We employed transmission electron microscope (TEM), Western blotting (WB), and nanoparticle tracking analysis (NTA) to identify biomarkers in the exosomes extracted from plasma of the three groups. The RNA levels of miR-205, CA125, HE4 and TCF21 genes in plasma exosomes were detected by real-time quantitative PCR (qRT-PCR) method. We used clinical pathological parameters and the Receiver Operating Characteristic (ROC) curves to evaluate the diagnostic efficacy for the genes detected in plasma exosomes. RESULTS: We found that the expression level of miR-205 in plasma exosomes of the OC group was significantly higher than that of the benign and control groups (P < 0.05), and the level of miR-205 was elevated during the III-IV periods of OC and lymph node metastasis. CONCLUSION: The level of miR-205 in plasma exosomes is a valuable tumor biomarker to improve OC diagnosis.