Recombinant alpha‐2b‐interferon enhances the circulating levels of a 90‐kilodalton (K) tumor‐associated antigen in patients with gynecologic and breast malignancies

The circulating levels of a 90‐kilodalton (K) tumor‐associated antigen were measured in the blood of 43 patients with gynecologic and breast malignancies who underwent a short course of recombinant alpha‐2b‐interferon (rIFN α‐2b) (3 million U/m2/d intramuscularly [IM] for 3 days). Of the 43 patients, 23 showed abnormal 90‐K levels (> 1.7 U/ml). A significant increase of antigen levels was already observed 24 hours after the first administration and persisted throughout the investigation period. Of 20 patients with 90‐K levels below the normal limit, 12 went over the normal cutoff value after two rIFN α‐2b injections. No significant modifications of 90‐K levels were detected in nine women receiving rIFN α‐2b for the treatment of genital condylomata. The serum levels of two other tumor‐associated antigens, CA 125 and CA 15‐3, were not modified by rIFN α‐2b administration. The ability of rIFN α‐2b to increase the circulating levels of 90‐K might have important clinical implications for the serodetection of cancer.