Estrogen content and DNA unwinding in tumor and normal endometrial tissue of aging endometrial cancer patients.

Over the past years, data on the role of DNA damage in hormonal carcinogenesis have been accumulated. In 21 endometrial cancer (EC) patients (mean age 61.8 +/- 1.6 years), no difference between malignant and normal endometrium in estradiol content (radioimmunological assay) and in alkali-induced DNA unwinding as a measure of DNA strand breakage (fluorometrical assay) was discovered. At the same time (contrary to normal endometrium), there were no correlations between the estradiol content in malignant endometrium with DNA unwinding or blood estrogen level. The estradiol concentration in malignant endometrium increases with age in menopausal EC patients, though no correlation between estrogen content in endometrial tissue and body weight was discovered. DNA unwinding rate in malignant endometrium correlates only with the concentration of steroid receptors in normal endometrial tissue. It may be possible that before the appearing of any neoplastic changes in the endometrium, a higher level of estradiol in the target tissue leads to DNA damage which may be considered as a factor predisposing to tumor development. Practically speaking this would mean that the estradiol content and DNA unwinding level in endometrial tumors may be used in future as indicators for therapeutic intervention (first of all, during the hormone therapy of EC) and also as markers for the evaluation of the effectiveness of the latter.