Androgen stimulation of gross cystic disease fluid protein and carcinoembryonic antigen in patients with metastatic breast carcinoma.

Plasma levels of carcinoembryonic antigen (CEA) and the 15,000 molecular weight gross cystic disease fluid protein (GCDFP-15) were determined in 30 patients with metastatic breast carcinoma before, during, and after treatment with fluoxymesterone. Within 2 weeks after initiation of treatment, plasma levels of GCDFP-15 increased 50% above basal values in 15 (79%) of 19 patients. Similar increases in plasma CEA levels occurred in only 5 (23%) of 22 patients. Eight (33%) of 24 patients achieved increases in GCDFP-15 of 500% or more above basal levels after 14-336 days of therapy. Within 2 weeks of fluoxymesterone termination, 14 (93%) of 15 patients had a decrease in plasma GCDFP-15 levels, and in 12 (80%) the decrease exceeded 33% (the inverse of a 50% increase). Conversly, only 5 (33%) of 15 patients experienced a decrease in plasma CEA levels within 2 weeks of therapy termination, and in only 1 (6.7%) subject did the decrement exceed 33%. Nine (90%) of 10 patients who had 50% increases in plasma GCDFP-15 during initial androgen therapy also had significant decreases in plasma GCDFP-15 following termination of therapy. Data on 3 prospectively studied patients demonstrated that plasma GCDFP-15 rose within 24 hours of initiation of fluoxymesterone therapy and continued to rise for at least 6 days. Increased plasma levels of GCDFP-15 were reflected in increased urinary excretion of the glycoprotein.