Biomarkers for ovarian cancer: New technologies and targets to address persistently unmet needs

Despite significant progress over the last three decades, ovarian cancer remains a formidable adversary. Many articles concerning biomarkers or therapy for this disease begin by pointing to the annual incidence, prevalence and low rate of cure. The fraction of women surviving 5 years has increased from 37% in 1974–1976 to 46% in 1999–2005 (P < 0.05) [1], but the overall cure rate – the plateau on the survival curve – has not changed despite more widespread utilization of cytoreductive surgery and combination chemotherapy with platinum based compounds and taxanes. The fraction of long term survivors depends not only upon the stage of the disease, but also on the grade of cancer and the ability to remove all, or nearly all, visible tumor nodules at the time of primary surgery. Failure to improve the rate of cure has been attributed to the persistence of dormant drug resistant cancer stem cells and to late diagnosis. Despite substantial research over the last 3 decades, an effective strategy for early detection of ovarian cancer remains an unmet need. The fact that survival correlates with stage, i.e., the presence and extent of metastasis, has provided a rationale for screening and early detection. When epithelial cancer is diagnosed while still limited to the ovaries (stage I), five year survival rates approach or exceed 90%. Spread to other pelvic organs (stage II) is associated with disease control in up to 70% of cases. When disease has metastasized to the abdomen (stage III) or