Ectopic production of pregnancy-specific beta 1-glycoprotein by a nontrophoblastic tumor in vitro.

To demonstrate the ectopic production of pregnancy-specific beta 1-glycoprotein (PSbetaG) by a nontrophoblastic tumor, the in vitro secretion of this glycoprotein was evaluated in an hCG-producing ovarian cystadenocarcinoma cell line maintained in long term cell culture. Parallelism was demonstrated between the immunoreactive material present in the tissue culture media and highly purified PSbetaG measured by a sensitive and specific RIA. The immunoreactive material was shown to cochromatograph with purified PSbetaG present in normal term pregnancy serum on a Sephadex G-150 column. The tumor PSbetaG was adsorbed to concanavalin A-Sepharose and eluted with alpha-D-methyl-glucoside in a manner similar to purified PSbetaG. The indirect immunoperoxidase method with anti-PSbetaG sera localized PSbetaG in secretory vesicles and in the endoplasmic reticulum of the tumor cells by light and electron microscopy. The addition of sodium butyrate to the tissue culture media stimulated PSbetaG production in a fashion quantitatively similar to that seen with hCG. The number of PSbetaG-staining intracellular vesicles also increased after exposure to butyrate. These studies provide direct evidence for the ectopic production of PSbetaG by a nontrophoblastic tumor cell line.

Malignant Leydig cell tumor: objective tumor response to o,p'-DDD.

Leydig cell carcinoma of the testicle is a rare tumor with 16 well-documented cases in the medical literature. Radiotherapy and chemotherapy have not been successful in treating patients with metastatic disease. The patient described in this report had widely metastatic Leydig cell carcinoma associated with hypertension, hypokalemic alkalosis, and an elevated serum concentration of desoxycorticosterone. He experienced an objective clinical remission and disappearance of pulmonary metastases while receiving o,p'-DDD as the sole chemotherapeutic agent. This response was similar to that found in patients with adrenal cortical carcinoma. The regression of this tumor with an adrenolytic agent, in conjunction with the similar morphologic and biochemical features of these two types of tumors, provides additional evidence of the close similarity between Leydig cell carcinoma and adrenal cortical carcinoma.