Patient samples

Ascites and primary tumours were obtained from 23 HGSOC patients at the time of debulking surgery at Shanghai Cancer Center, Fudan University, from 2013 to 2014 (Table S4); the patients had a median age of 67 (54–78) years old. All patients were in stage III/IV. In addition, 98 HGSOC patients (7 patients in stage I/II; 91 patients in stage III/IV) who received surgery at Obstetrics & Gynecology Hospital, Fudan University, from 2009 to 2012 were included in our retrospect cohort with a median follow-up of 60 (26–77) months. The pathological characteristics of these patients are listed in Table S5. Control OSE tissues were obtained from 82 patients who were diagnosed with hysteromyoma undergoing post-unilateral uterine adnexectomy, who had a median age of 51 (45–55) years old.

All the patients’ diagnoses in this study were pathologically confirmed, and no patients received pre-operative chemotherapy or had a family history of breast or ovarian cancer. The proposal for this study was approved by the Institutional Review Board of Obstetrics & Gynecology Hospital, Fudan University, (2016-29), and informed consent was obtained from all subjects.