MiR-575 in Exosomes of Vaginal Discharge Is Downregulated in Ovarian Cancer Patients

Ovarian cancer is asymptomatic in its early stages, and often diagnosed at advanced stages, leading to a high recurrence rate. In recent years, exosomes have been shown to be useful for early-detection, prognosis prediction, and treatment of cancer. Although many studies of cancer-related exosomes using other bodily fluids have been reported, there are few studies examining vaginal discharge, but none related to ovarian cancer. In this study, we investigated a method for early-detection of ovarian cancer using vaginal discharge, which are physically close to the fallopian tubes, where ovarian cancer originates, and can be easily collected from outside the body.

Vaginal discharge was collected from 30 patients with ovarian cancer and 29 patients with benign gynecological diseases, and exosomal miRNAs were extracted. Samples from each group were submitted to miRNA microarray in order to examine miRNAs with significant differences in expression levels. We further narrowed down the list to four miRNAs based on literature and microarray data and examined the expression levels of miRNAs in the malignant and benign groups by RT-qPCR.

MiR-575 expression was significantly decreased in the malignant group compared to the benign group (p=0.00861). qPCR results were analyzed for several patient characteristics and no significant differences were found.

This is the first study to investigate exosomal miRNAs in vaginal discharge of ovarian cancer. Exosomal miR-575 in vaginal discharge may be used as a biomarker for ovarian cancer.