Estrogen and progesterone receptors in endodermal sinus (yolk sac) tumor. Evaluation of immunocytochemical and biochemical methods.

Frozen tissue from four ovarian and two testicular endodermal sinus (yolk sac) tumors was studied with both biochemical and immunocytochemical methods to detect the presence of estrogen receptors (ERs) and progesterone receptors (PRs). Using the biochemical assay, one of the ovarian tumors was shown to contain low levels of ERs, whereas in the remaining five tumors no ERs were detected, and PRs were undetectable in all six tumors. In the frozen sections immunostained for ERs and PRs, no specific nuclear staining was detected in any of the six tumors. Since the immunocytochemical method provides a more tissue-specific evaluation of hormone receptors, the low level of ERs detected in one tumor using the biochemical assay is attributed to nonspecific binding. It appears that endodermal sinus tumor expresses neither ERs nor PRs.