To analyze the proportion of hereditary tumors in ovarian cancer patients in China, as well as the spectrum of variations; the ctDNA characteristics in patients with ovarian cancer; the correlation between the clonal status of mutations and therapy response; whether ctDNA detection can be used to predict the risk of ovarian cancer recurrence; and the characteristics of immune repertoire before and after treatment in patients with ovarian cancer.

100 OC cases with available matched tumor DNA and plasma will be collected. All patients will be treated according to clinical guidelines, and receive circulating tumor DNA (ctDNA) liquid biopsy at the time of diagnosis, at mid treatment, at the end of treatment and during follow-up. The study will be ended when the patients have progressive disease (PD) or reach the longest follow-up time (2 years).

Inclusion Criteria:

• Patients who have not received treatment including radiotherapy, chemotherapy, and surgery.
• Expected to achieve satisfactory tumor cytoreductive surgery.
• Estimated lifetime is more than 3 months.
• Understand the research plan and voluntarily participate in the study, sign the informed consent form.
• Ability to collect specimens from each time point and provide corresponding clinical information.

Exclusion Criteria:

• Patients who will receive new adjuvant therapy.
• Patients who have other primary cancer.
• Pregnant or breast-feeding woman.
• Patients with severe mental illness.
• Patients achieve unsatisfactory tumor cytoreductive surgery.
• Patients who voluntarily withdraw for any reason.
• Patients who cannot complete the research plan.

Patients with previously untreated Ovarian Cancer.