Extracellular microRNA profiling for prognostic prediction in patients with high-grade serous ovarian carcinoma.

High-grade serous ovarian carcinoma is a leading cause of death in females worldwide. MicroRNAs are stable non-coding RNAs in the peripheral blood that reflect a patient's condition, and therefore, they have received substantial attention as non-invasive biomarkers in various diseases. We previously reported the usefulness of serum microRNAs as diagnostic biomarkers. Here, we investigated the prognostic impact of the serum microRNA profile. We used the GSE106817 dataset, which included preoperative microRNA profiles of patients with ovarian malignancies. Excluding patients with other malignancy or insufficient prognostic information, we included 175 patients with high-grade serous ovarian carcinoma. All the patients except the four patients underwent surgery and received chemotherapy as initial treatment. The median follow-up period was 54.6 months (range 3.5-144.1 months). Univariate Cox regression analysis revealed that higher levels of miR-187-5p and miR-6870-5p were associated with both poorer progression-free survival and overall survival, and miR-1908-5p, miR-6727-5p, and miR-6850-5p were poor prognostic indicators of progression-free survival. The overall survival and progression-free survival prognostic indices were then calculated using the expression values of three prognostic microRNAs. Multivariate Cox regression analysis showed that both indices were significantly independent poor prognostic factors [Hazard ratio for overall survival and progression-free survival, 2.343 (p = 0.015) and 2.357 (p = 0.005), respectively]. In conclusion, circulating microRNA profiles can potentially provide information to predict the prognosis of patients with high-grade serous ovarian carcinoma. Therefore, there is a strong demand for early clinical application of circulating microRNAs as non-invasive biomarkers.