HUMAN CHORIONIC-GONADOTROPIN (HCG) AND ITS FREE SUBUNITS IN HYDROCELEFLUIDS AND NEOPLASTIC TISSUE OF TESTICULAR CANCER-PATIENTS - INSIGHTSINTO THE IN-VIVO HCG SECRETION PATTERN

To obtain insight into the secretion pattern of human chorionic gonado tropin (hCG) and its free subunits, hCG alpha and hCG beta, in vivo, w e analyzed hydrocele fluids of 13 patients with testicular cancer and correlated the respective values to those of cubital vein and testicul ar vein serum. As a control population, patients with nonmalignant hyd roceles (n = 11) were studied. Analyses were performed with a set of h ighly sensitive and specific time-resolved fluoroimmunoassays based on our own panel of monoclonal antibodies. In the collective of testicul ar cancer patients, increased hydrocele levels of either hCG or free h CG alpha or free hCG beta mere observed in 77, 54, and 92% of cases; t he corresponding percentages for cubital vein serum were 62, 23, and 3 1%. The cubital vein ratio of hCG:hCG alpha (546:1) and hCG:hCG beta ( 51:1) decreased to 63:1 and to 7:1 in the hydrocele fluids. Surprising ly, hydrocele fluids of five patients with pure seminoma, who were neg ative for the three markers in the periphery, revealed an elevation of free hCG beta in all cases, while hCG alpha and holo-hCG were elevate d twice. Final proof that hCG beta and hCG alpha are indeed produced b y these previously termed ''marker negative'' seminomas has been achie ved by reverse transcripta-polmerase chain reaction with primers speci fic for the a-subunit and the four most abundantly transcribed hCG bet a genes 3, 5, 7, and 8. From these data, we conclude that: (a) seminom atous and nonseminomatous testicular cancers, irrespective of histolog y, secrete hCG and its free subunits; (b) the amount of free subunits being secreted in vivo by these tumors has been underestimated; and (c ) the classification in marker-positive and marker-negative testicular cancer should he reconsidered.