BOVARY-Pilot is a monocentric prospective transversal pilot study with a total duration of 6 months. The purpose of this study is to determine the feasibility of detecting somatic tumor mutations in the blood of patients with ovarian cancer in order to determine whether a blood test can replace a tissue biopsy to prescribe a personalized treatment. The method will consist of a single blood sample during the patient's visit and prior to the establishment of any newly diagnosed cancer treatment. The concordance of somatic mutations (SNV) found in tissue and in cell-free DNA (cfDNA) extracted from blood will then be compared

Inclusion Criteria:

• Age ≥ 18 years
• Patient with stage III to IV non-treated high grade ovarian cancer or recurrent high grade ovarian cancer
• Adequate haemoglobin rate ≥ 9 g/dL
• Patient who can benefit from an additional blood sample of 20ml. The total volume of each sample meets with the indications of the Order in force establishing the list of researches mentioned in 2 ° of Article L. 1121-1 of the Public Health Code.
• Availability of tumor samples from biopsy or surgery
• Patient affiliated to a social security scheme
• Ability to provide written informed consent

Exclusion Criteria:

• Any concurrent severe and/or uncontrolled medical conditions which could compromise participation in the study
• Contraindication to a blood sample of 20 mL
• Pregnant or breast-feeding women
• Ongoing treatment for the newly diagnosed cancer or the recurrence
• Patient pre-treated with poly-ADP-ribose-polymérase-1 (PARP) Inhibitors
• Patient under guardianship or curatorship or deprived of liberty.