Choriocarcinoma: expression of tumor- and trophoblast-associated antigens in patients with low chorionic gonadotropin excretion.

The circulating levels of four tumor- or trophoblast-associated antigens were measured by specific radioimmunoassays in 11 patients with gestational choriocarcinoma. The estimations were carried out at the time when the urinary gonadotropin (hCG) excretion was low or negligible. Gonadotropin, measured as the hCG beta-subunit, was detected in serum of three patients, one of whom also showed a slightly raised level of carcinoembryonic antigen (CEA). All patients had normal serum alpha-fetoprotein (AFP) levels and no trace of human placental lactogen could be demonstrated. Repeat estimation after treatment of patients with raised levels showed a disappearance or a marked decrease of the circulating hCG levels and a return to normal of the elevated serum CEA level. The results show that although CEA levels may occasionally be elevated new information can hardly be expected from markers other than hCG when one is monitoring response to treatment, but AFP may have potential significance in the distinction between pregnancy and a trophoblastic disease. The circulating levels of hCG are of vital importance in the monitoring of choriocarcinoma patients who appear to be in remission by the conventional analysis of urinary hCG excretion.