Early primary diagnosis of ovarian cancer and detection of recurrence by serum cystine aminopeptidase assay.

The aim of this study was to correlate the relationship between serum cystine aminopeptidase (CAP) activity in normal patients and that in patients with primary ovarian cancer of recurrence. Sera obtained from 63 patients and evaluated for CAP activity by the method of Babuna and Yenen were grouped as follows: in 20 normal, nonpregnant patients, the mean activity was 25; in 14 patients with fibromas of the uterus, it was 38; in two patients with ovarian sarcoma, the activities were "normal" (24 to 27); and in 27 patients with primary ovarian adenocarcinoma or recurrence, the activity corresponded to the size of the tumors. Assay of serum CAP activity is a simple procedure which can be performed in any laboratory. It is a quick method for qualitative, and even quantitative, assessment of an ovarian adenocarcinoma in the nonpregnant patient. It may prove to be especially valuable in the follow-up of patients with ovarian cancer.