An immunohistochemical study of steroid binding by endometrial glandular epithelial cells throughout the menstrual cycle

Thymidine phosphorylase expression in normal and hyperplastic endometrium

AIMS

To investigate the expression of thymidine phosphorylase (TP), a known angiogenic factor for endothelial cells, in normally cycling endometrium and various forms of endometrial hyperplasia.

METHODS

TP expression was assessed with the P-GF.44C monoclonal antibody, using the alkaline phosphatase anti-alkaline phosphatase method. Ninety two normal and hyperplastic endometria were studied.

RESULTS

In normal proliferative endometrium, TP is found exclusively in the basal layer and the inner third of the functionalis; expression is cytoplasmic in glandular epithelium and nuclear in stromal cells. It is invariably patchy. This immunohistochemical picture remains almost unaltered during the early and mid secretory phase of the normal menstrual cycle but, most impressively, TP is expressed uniformly in the epithelium of all endometrial glands towards the end of the cycle. At this stage, expression is mixed nuclear/cytoplasmic and there is very little stromal nuclear staining. In simple endometrial hyperplasia, the staining pattern for TP is identical to normal proliferative endometrium, with a distribution that is usually limited to a few rather weakly proliferating glands and to the adjacent periglandular stroma of the deep endometrium. The distribution is more extensive in complex and atypical endometrial hyperplasias, where a mixed nuclear/cytoplasmic pattern usually prevails over the pure cytoplasmic reaction.

CONCLUSIONS

TP is expressed consistently in normal and hyperplastic endometrium, suggesting a role in physiological and pathological angiogenesis. In normal endometrium, TP has a definite pattern of distribution, which is dependent on the phase of the menstrual cycle, whereas in all forms of endometrial hyperplasia the enzyme is randomly distributed and lacks an orderly pattern.

Immunohistochemical estrogen receptor assessment in hyperplastic, neoplastic, and physiologic endometria

Endometrial hyperplasias and some endometrial carcinomas arise in a setting of estrogen excess. Steroid hormones interact with cells via specific receptors; assessing receptor levels may indicate a tissue's potential for interaction with that hormone. To examine estrogen receptor (ER) levels in endometrial hyperplasia, endometrial carcinoma, and physiologically cycling endometrium, an immunohistochemical technique utilizing a monoclonal anti-estrophilin (estrogen receptor) antibody was applied to formalin-fixed, paraffin-embedded tissue. In complex hyperplasia and grade I adenocarcinoma, the mean percentages of epithelial cells demonstrating nuclear staining for ER was mildly decreased compared to proliferative endometrium. A trend was noted toward less ER staining in atypical hyperplasia compared to non-atypical complex hyperplasia. ER varied with physiologic cycling of the endometrium. ER was also present in atrophic endometrium, myometrium, adenomyosis, and leiomyomata. Immunohistochemistry permits localization of ER and is a useful technique in ER assessment of endometrial hyperplasias and carcinomas.