Correlation of female sex steroid hormone receptors with histologic and ultrastructural differentiation in adenocarcinoma of the endometrium

A series of 43 patients with endometrial adenocarcinoma were evaluated in order to investigate the relationships of the estrogen receptor (ER) and the progesterone receptor (PR) with the histologic and nuclear grades and the ultrastructural differentiation of these tumors. Twenty‐six neoplasms were positive (10 fmole/mg protein) for both receptors, 1 was positive for the ER only, 9 were ER−PR+, and 7 were ER−PR−. Twenty carcinomas were histologic Grade I, 12 Grade II, and 11 Grade III. Distribution of nuclear grade was 11 Grade I, 18 Grade II, and 14 Grade III. Both histologic and nuclear grades were found to be significantly related to the presence or absence of both the ER and the PR. Several cytoplasmic structures (cilia, primary lysosomes, intracytoplasmic lumens) were highly specific but of low sensitivity for predicting the receptor status of these tumors. To a limited extent, ultrastructural markers were associated with histologic differentiation.