Because early ovarian cancer is generally an asymptomatic process, the majority of cases are diagnosed at a late stage, when they are incurable. A precursor lesion, while thought by many to exist, has so far not been successfully identified. While CA-125 is a useful test for the follow-up of patients with established ovarian cancer, it has not led to earlier detection when used alone as a marker. Similarly, ultrasound, although a sensitive test, is not sufficiently specific to be utilized for screening. The combination of CA-125 and ultrasound is currently being studied and may ultimately prove to be an effective screening method for postmenopausal and high-risk women. Research is also under way to identify markers that have sufficient sensitivity and specificity to be utilized in the screening of asymptomatic women; the hope is to ultimately develop a panel of markers for early detection.