Soluble interleukin‐2 receptor alpha is elevated in sera of patients with benign ovarian neoplasms and epithelial ovarian cancer

Background. Previous studies have established that soluble interleukin‐2 receptor alpha (sIL‐2Rα) levels are elevated in ascites and sera from individuals with advanced ovarian cancer (International Federation of Gynecology and Obstetrics [FIGO] Stage III/IV). This study was undertaken to evaluate sIL‐2Rα levels in individuals with benign ovarian neoplasms and early stage ovarian cancer (FIGO Stage I/II). Comparison with CA 125 levels was performed to assess screening potential. Methods. Sera from 92 healthy individuals, 61 with benign adnexal masses, 12 patients with FIGO Stage I/II ovarian cancers, and 27 patients with FIGO Stage III/IV ovarian cancers were assayed for sIL‐2Rα by enzymelinked immunosorbent assay and CA 125 by radioimmunoassay. Results. The mean serum sIL‐2Rα levels for benign pelvic masses, and Stage I/II and Stage III/IV epithelial ovarian cancer were 1507±82, 1631±274, and 2596±384 U/ml, respectively. The difference between mean serum sIL‐2Rα levels in individuals with benign adnexal masses and Stage III/IV epithelial ovarian cancer was statistically significant (P < 0.05). In addition, of the four individuals with FIGO Stage I/II ovarian cancer who had CA125 levels below 35 U/ml, the accepted upper limit of normal, three patients had elevated serum sIL‐2Rα levels. Eleven of 12 patients (92%) with potentially curable Stage I/II disease had elevated serum levels of either sIL‐2Rα or CA125 and 8 of 12 (67%) had elevations of both sIL‐2Rα and CA125. Sensitivity and specificity of a combination of CA 125 and soluble IL‐2R alpha were 88.5% and 27.1%, respectively. Conclusion. Soluble interleukin‐2 receptor alpha levels do not appear to differentiate between benign adnexal lesions and early malignancy; however, measurement of sIL‐2Rα levels in combination with CA125 warrants further evaluation to determine if together they will identify individuals with Stages I and II ovarian cancer. Cancer 1995;76:1615–20.