OVX1 AS A MARKER FOR EARLY-STAGE ENDOMETRIAL CARCINOMA

Background. Endometrial carcinoma is generally diagnosed only after th e onset of postmenopausal bleeding. Although most patients with Stage I disease can be cured, the prognosis worsens significantly when the t umor is no longer confined to the uterine corpus. Serum CA 125 is elev ated in only 10-20% cases of Stage I and II endometrial carcinoma. A s erum tumor marker that can detect early stage endometrial cancer might aid in management of the disease. Methods. An OVX1 double-determinant radioimmunoassay was used to detect an epitope on a high-molecular-we ight mucinlike glycoprotein found in the sera of 45 patients with endo metrial cancer. Results. Apparently healthy persons had serum OVX1 ant igen levels of 2.23 plus or minus 2.48 U/ml (mean +/- standard deviati on). Elevated levels of OVX1 antigen (> 7.2 U/ml) were found in 5% of 184 healthy persons and in 64% of 45 patients with endometrial cancer. OVX1 antigen was elevated in 64% of 36 patients with Stage I, 50% of 2 patients with Stage II, 60% of 5 patients with Stage III, and each o f 2 patients with Stage IV endometrial cancer, but only 8.6% of 58 pat ients with endometriosis. Elevation of serum OVX1 was found more frequ ently in patients with deep myometrial invasion and with poorly differ entiated tumors (P < 0.01). Conclusions. The OVX1 antigen deserves fur ther evaluation as a marker for early detection of endometrial cancers and as a prognostic factor for women with apparent early stage diseas e.