This is a research study to look at differences in tumor tissue from ovarian cancer patients that may help to determine response and resistance to treatments.

Ovarian cancer participants will be asked to have two tumor biopsies during the research study. The first biopsy will be done prior to receiving the participants' assigned treatments as a part of their cancer care and the second biopsy will be done about 3-7 days after starting treatment. Participants who will undergo neoadjuvant treatment and then surgery, will also have their tumor tissue collected during surgery. Participants whose disease worsens while on treatment will also be asked to have an additional, optional tumor biopsy.

The tumor tissue samples will be studied to look at certain proteins and enzymes, including enzymes called kinomes, that may be important in determining response and resistance to the treatment that participants will receive as a part of their cancer care.

Inclusion Criteria:

• Age ≥18 years.
• Histological diagnosis of epithelial ovarian cancer
• Eastern Cooperative Oncology Group (ECOG) performance status ≤2.
• Life expectancy of greater than 3 months
• Diagnosis of epithelial ovarian cancer undergoing chemotherapy as part of standard care or a clinical trial OR receiving a targeted therapy with a targeted agent
• Must be agreeable to paired biopsies
• Must have disease amenable to paired biopsy.
• Ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria:

• Any contraindication to biopsy
• Need for anticoagulation that cannot be interrupted

Patients with histological diagnosis of epithelial ovarian cancer