Immunosuppressive acidic protein in patients with ovarian cancer.

Serum immunosuppressive acidic protein (IAP) was determined in 63 patients with ovarian tumors (33 benign and 30 malignant) and 79 healthy female controls, and was examined as a marker for ovarian cancer in comparison with carcinoembryonic antigen (CEA). The mean value of serum IAP in patients with ovarian cancer (1085 +/- 474 micrograms/ml) was statistically higher than those of both benign tumors (394 +/- 93 micrograms/ml) and controls (298 +/- 92 micrograms/ml). Elevated levels of IAP and CEA were found in 93.3% and 30.0% of patients with ovarian cancer, respectively. There were three false-positive cases with IAP and two with CEA. Elevation of IAP was recognized in all cancer patients in Stage I, whereas 33.3% of these patients showed elevated CEA. The occurrence of elevated serum IAP was not affected by tumor histologic features. Serial IAP determination appeared to provide a useful follow-up marker in patients in whom CEA was low in value. The measurement of serum IAP is highly recommended as an addition to the conventional diagnostic methods.