Collection of clinical samples

Written informed consent was obtained from all patients. Serum and ascites samples of patients with stage III to IV HGSOC were collected during surgery at Nagoya University Hospital, Nagoya, Japan (n = 22) between 2019 and 2021. Normal ovarian and uterine tissues were also obtained from five patients. The study was conducted with the approval (no. 2017-0053) by the Institutional Review Board of Nagoya University Hospital. Ascites samples of HGSOC patients were also collected during surgery at the National Cancer Center Hospital, Tokyo, Japan (n = 28) between 2015 and 2017. The protocol was approved (no. 2014-164) by the Institutional Review Board of the National Cancer Center.

Serum samples were centrifuged at 3000 rpm for 10 min at room temperature. Ascites samples were centrifuged at 300g undiluted for 5 min at 4°C to remove cell debris. The serum and ascites samples were stored at −80°C until further use.