- A retrospective review of all patients entered will be performed to confirm clear cell histology; patients must have recurrent or, progressive clear cell ovarian cancer not solely based on cancer antigen (CA)-125; primary tumors must be at least 50% clear cell histomorphology in order to be eligible or have a histologically documented recurrence with at least 50% clear cell histomorphology; recurrence should be biopsy proven unless the tumor is located in an area deemed unsafe to biopsy by the surgeon; if a biopsy can be obtained without significant risk, then biopsy should be obtained