Abstract
We determined DNA content, S-phase fraction, and estrogen (ER) und progesterone receptor (PR) levels in 36 stage I endometrial adenocarcinomas and in 22 hyperplastic lesions to obtain information on the genesis and progression of endometrial malignancy. DNA aneuploidy was detected in 12/36 (33%) carcinomas and in none of the hyperplastic lesions. DNA aneuploidy was significantly more common in poorly and moderately differentiated carcinomas than in the well-differentiated ones. Similarly, the highest number of cells in S-phase were found in poorly and moderately differentiated carcinomas, whereas well-differentiated carcinomas and all hyperplasias had an equally small S-phase fraction. Mean ER and PR levels were highest in hyperplastic lesions, especially those with atypical features, whereas carcinomas of all grades had significantly lower values. Thus, it is likely that the loss or decreased expression of steroid receptors is an early event during carcinogenesis in human endometrium, whereas an increase in the cell proliferation rate and the formation of DNA aneuploidy occur later during tumor progression.